IC-NRLF 


SB    E77    77E 


'e*  .,  ' 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

OF* 


Ctes 


SOME 

REACTIONS  OF  ACETYLENE 


DISSERTATION 


SUBMITTED  TO  THE  FACULTY  OF  PHILOSOPHY  OF  THE  CATHOLIC 

UNIVERSITY  OF  AMERICA  FOR  THE  DEGREE  OF 

DOCTOR  OF  PHILOSOPHY 


BY 


JULIUS  A.  NIEUWLAND,  C.  S.  C. 


NOTRE  DAME   UNIVERSITY  PRESS 

NOTRE   DAME,  INDIANA 
IQ04 


ACKNOWLEDGMENT. 


The  work  about  to  be  described  was  suggested  by 
Prof.  John  J.  Griffin  and  carried  on  under  his  guid- 
ance. I  express  to  him  ray  sincere  thanks  for  the 
kind  counsel  and  instruction  received  during  my 
course  of  chemistry  at  the  Catholic  University.  I 
gratefully  acknowledge  my  obligations  also  to  Prof. 
E.  Greene,  Prof.  E.  Pace,  and  Dr.  T.  Shields,  under 
whom  I  pursued  my  studies  in  botany,  experimental 
psychology,  and  biology  respectively. 


THE  HYDROGENATION  OF  ACETYLENE. 


THE  HISTORY  OF  THE  SYNTHESIS  OF  ETHYI.ENE. 

Numerous  attempts  have  been  made  to  unite  acet- 
ylene with  hydrogen  to  form  ethylene  or  ethane. 
The  first  combination  of  acetylene  with  hydrogen 
was  effected  by  Wilde,1  who  united  them  by  pass- 
ing the  gases  over  platinum  black,  ethylene  being 
formed.  The  residual  gas  did  not  give  the  acetylene 
reaction  with  ammoniacal  cuprous  chloride,  and  was 
absorbed  by  fuming  sulphuric  acid. 

Berthelot2  succeeded  in  obtaining  ethylene  from 
acetylene  given  off  from  copper  acetylide  in  the  pres- 
ence of  nascent  hydrogen.  The  gases  were  obtained 
from  zinc  and  from  copper  acetylide  in  ammonia 
water.  Hydrogen  from  an  acid  solution  did  not  give 
a  good  yield  of  ethylene.  The  ethylene  was  separ- 
ated from  the  acetylene  with  difficulty,  as  the  two 
hydrocarbons  dissolved  in  the  ammoniacal  cuprous 
chloride.  The  latter  gas,  however,  formed  a  precipi- 
tate of  copper  carbide,  from  which  the  acetylene 
could  be  determined  gravimetrically,  and  the  ethylene 
could  be  calculated  volumetrically  by  boiling  the  solu- 
tion of  the  cuprous  chloride,  when  the  gas  was 
evolved  from  the  solution,  and  measured  after  wash- 
ing free  from  ammonia. 


1  Ber.    7.    353.     (Bull,  d'  Acad.    Royal   de    Belg.  2,  XXI., 
No.  i.  (1864). 

2  Ann.  Chim.  Phys.  3,  LXVIL,  51,  (1863.) 

3 


1  57' 


-  4  - 

Berthelot1  likewise  showed  that  when  a  mixture  of 
hydrogen  and  acetylene  was  heated,  ethylene  was  one  of 
the  products.  He  accounted  for  the  formation  of  the 
ethylene  in  two  ways,  first  by  direct  addition,  when 
the  action  represented  by  the  equation,  C2H2H-H2  = 
C2H4,  took  place.  As,  however,  the  yield  of  the 
ethyleue  was  too  small  to  correspond  to  this  reaction, 
another  mode  of  formation  was  suggested,  namely : 
2C2H2  =  C2H4-f-2C.  Ethylene  likewise  underwent 
decomposition  into  acetylene  and  ethane  :  2C2H4  = 
C2H2+C2H6.  If  hydrogen  were  present  it  united 
with  the  ethylene  to  form  ethane. 

In  1895,  N.  Caro2  claimed  that  he  had  obtained 
alcohol  from  acetylene.  This  gas  and  hydriodic  acid 
gave  ethylene  di-iodide,  or  ethylidene  di-iodide,  and 
this  product  being  boiled  with  a  concentrated  solution 
of  caustic  potash  gave  potassium  acetate,  acetylene 
and  alcohol.  Seventy  grams  of  alcohol  were  said  to 
have  been  obtained  in  one  operation.  When  the 
di-iodide  was  decomposed  with  silver  hydroxide,  only 
small  quantities  of  acetylene  were  obtained,  together 
with  90  percent,  potassium  acetate  and  alcohol.  (!) 
The  di-iodide  of  ethylene  heated  in  closed  tubes  with 
water  gave  a  yield  of  alcohol  that  amounted  to  40 
per  cent,  of  the  theoretical. 

Kru'ger  and  Pueckert3  repeated  Caro's  work,  and 
found  that  they  could  make  50  grams  of  di-iodide 
in  three  months  and  from  this  no  alcohol  could  be 
obtained,  though  aldehyde  was  shown  to  be  present. 

1  Ann.  Chim.  Phys.  4,  IX.,  431. 

2  Cent.  (1895)  2,  437.  Chem.  Ind.  18,  226. 

3  Chem.  Ind.  18,  454. 


—  5  — 

Caro  repeated  his  work,  but  could  not  obtain  his 
previously  published  results  and  acknowledged  his 
mistake. 

Kru'ger1  could  not,  moreover,  succeed  in  uniting 
acetylene  with  nascent  hydrogen,  as  Berthelot2  had 
claimed.  In  1894,  an  article  was  published  by 
Frank3  advocating  the  commercial  manufacture  of 
alcohol  thus  prepared  by  the  action  of  acetylene  on 
nascent  hydrogen.  The  ethylene  formed  was  to  be 
led  into  ordinary  strong  sulphuric  acid.  This, 
diluted  and  boiled  with  water,  would  give  alcohol. 
The  acid  would  be  again  concentrated  and  used. 
This  process  was  represented  by  the  following  reac- 
tions : 

C2H2-{-  H2 = C2H4, 

HO  C2H5O 

C2H4+        >SO2=  >SO2, 

HO  HO 

C3H5O  HO 

>  SO2+ HOH  =        >  S02+  C2H5OH . 
HO  HO 

In  1899  and  1900,  Sabatier  and  Senderens*  studied 
the  action  of  finely  divided  metals  such  as  nickel, 
cobalt,  copper,  and  iron  on  a  mixture  of  hydrogen 
and  acetylene,  and  found  that  under  certain  condi- 
tions of  temperature  and  time,  ethylene,  ethane  and 


1  Chem.  Ind.  18,  459. 

2  Compt.  Rend.  54,  515. 

3  Chem.  Ind.  18,  74.  (1894). 

4  Compt.  Rend.  128,  173,  and  130,  1559,  1628, 1762. 


—  6  — 

other  hydrocarbons  of  the  aliphatic  and  aromatic 
series  were  obtained. 

In  1902,  the  addition  of  hydrogen  to  acetylene  was 
effected  electrolytically  by  Bilitzer.1  He  electro- 
lyzed  acetylene  gas  dissolved  in  a  solution  of  sodium 
potassium  and  ammonium  hydrates,  and  in  sulphuric 
acid.  In  the  alkaline  electrolytes  depolarization  with 
the  union  of  acetylene  and  the  electrolytic  hydrogen 
took  place  with  a  platinized  platinum  cathode,  but 
not  with  plates  of  platinum  or  nickel.  In  sulphuric 
acid  solutions  of  acetylene  with  platinized  platinum 
electrodes  the  products  were  ethylene,  ethane,  and 
hydrogen,  according  to  the  strength  of  the  current 
used.  The  hydrogenation  of  the  acetylene  was  ef- 
fected only  when  very  weak  currents  were  employed. 
This  seems  to  show  that  the  action  was  entirely  a 
mechanical  one,  for  when  strong  currents  were  used 
the  platinum  electrodes  would  become  coated  with 
gas  and  prevent  the  access  of  the  acetylene  to  the 
finely  divided  platinum  on  the  surface  of  the  electrode. 
The  acetylene  was  absorbed  with  ammoniacal  silver 
nitrate,  the  ethylene  with  fuming  sulphuric  acid. 
Hydrogen  and  ethane  were  determined  by  explosion. 
Bilitzer  worked  with  very  small  quantities  and 
claimed  yields  of  ethylene  and  ethane  entirely 
quantitative,  measured  by  the  law  of  electrochemical 
equivalents. 

In  a  solution  of  normal  sulphuric  acid,  alcohol  was 
supposed  to  be  formed  at  the  mercury  cathode,  pre- 
sumably due  to  the  reduction  of  aldehyde  formed  by 

1  Monats.  f.  Chem.  XX III.,  203. 


U»- 

|  UNlVt: 
XT,   —  7  — 

^*^*5i 


the  action  of  the  sulphuric  acid  on  the  acetylene. 
Traces  of  alcohol  were  vouched  for.  The  alcohol  was 
indicated  by  the  potassium  bichromate  and  iodoform 
reactions.  The  author  wished  to  obviate  any  mistake 
and  passed  acetylene  into  a  portion  of  the  acid  with- 
out using  any  current.  Only  the  odor  of  iodoform 
was  noticed.  When  the  current  was  passed  through 
the  solution  for  the  same  length  of  time  as  in  the 
previous  experiment,  a  fine  but  perceptible  precipitate 
of  iodoform  was  obtained.  Therefore  the  author  con- 
cluded that  in  the  second  instance  the  precipitate  of 
iodoform  was  due  to  the  alcohol  formed  at  the 
cathode.  The  author  did  not  suppose  that  acetylene 
was  changed  to  ethylene  in  an  acid  solution,  but 
thought  that  the  aldehyde  present,  especially  at  the 
mercury  cathode  was  reduced  to  alcohol  at  that  pole. 
Now  this  presupposes  that  the  aldehyde  was  present 
before  the  alcohol  was  formed.  Alcohol  may  have 
been  present,  but  the  iodoform  test  does  not  demon- 
strate its  presence  when  a  primary  aldehyde  is  in 
solution  with  it.  Acetaldehyde  will  give  the  iodo- 
form reaction  far  more  readily  than  alcohol,1  and  so 
no  reliance  can  be  put  in  this  test.  Bilitizer  accord- 
ingly concluded  that  with  platinized  platinum  elec- 
trodes depolarization  takes  place  at  the  cathode,  and 
that  the  products  in  an  alkaline  solution  are  ethylene, 
and  ethane  when  low  potentials  are  used.  In  a  sul- 
phuric acid  solution  with  a  cathode  of  mercury,  small 
quantities  of  acetylene  are  changed  to  traces  of 
alcohol.  The  improbability  of  this  conclusion  will  be 


1  Lieben, — Ann.  Supp.  7,218  and  377. 


more  evident  after  considering  the  results  I  obtained 
in  the  electrolysis  of  various  solvents  with  electrodes 
of  calcium  carbide. 

In  the  December  number  of  Electrochemical  In- 
dustry of  the  year  1902,  there  appeared  the  review  of 
a  patent  granted  to  J.  W.  Harris,  for  the  manufacture 
of  ether  and  alcohol,  from  acetylene  by  electrolysis. 
The  method,  briefly  described,  is  as  follows.  Acety- 
lene is  introduced  into  sulphuric  acid  in  a  heated 
vessel,  so  that  the  gas  passes  under  a  conical  cathode 
of  metal.  "The  acetylene  is  said  to  unite  with  the 
nascent  hydrogen  at  the  cathode  to  form  ethylene. 
This  unites  with  sulphuric  acid  to  form  ethyl  sul- 
phuric acid.  The  anode  is  contained  in  a  porous  cell 
to  prevent  the  oxidation  of  the  contents  of  the  cell. 
When  the  electrolyte  contains  over  fifty  per  cent,  of 
water  alcohol  is  formed.  As  the  proportion  of  the 
water  diminishes  the  formation  of  ether  begins. 
Ethane  may  also  be  formed  but  this  is  to  be  prevented 
as  much  as  possible.  The  formation  of  the  products 
is  thus  accounted  for  : 

C2H2+  H2 = C2H4, 

C2H50 

C2H4-f-H2SO4=  >SO2, 

HO 

C2H50 

>  SOa+ HOH  =  C2H5OH+  H  2  SO4, 
HO 

C2H50 

and,  2          >S02+HOH  =  (C2H5)20+2H2S04, 
HO 


f\     -.-„--. 

C2H50 

or,  >S02-f-C2H5OH  =  H2S04+(C2H5)2O. 

HO 

It  was  suggested  that  the  union  of  acetylene  with 
nascent  hydrogen  might  be  effected  at  a  cathode  of 
calcium  carbide  in  an  electrolyte  of  appropriate  dilu- 
tion. Before  proceeding  to  this  attempt  it  was  deemed 
necessary  to  determine  the  action  of  sulphuric  acid  on 
acetylene  and  calcium  carbide,  and  whatever  simple 
reactions  might  take  place  in  such  a  cell.  There  is 
no  record  of  any  work  done  on  the  action  of  sulphuric 
acid  on  calcium  carbide.  Whatever  work  on  acety- 
lene has  been  done  refers  to  the  reaction  of  the  gas 
itself  with  sulphuric  acid. 

The  anode  products  of  the  electrolysis  were  studied 
by  Coehn,1  in  1901.  When  a  solution  of  caustic 
potash  was  electrolyzed  while  a  stream  of  acetylene 
was  passed  over  the  anode,  formic  acid  was  obtained. 
Sulphuric  acid  similarly  treated  gave  acetic  acid. 

ACTION  OF  SULPHURIC  ACID  ON  ACETYLENE. 

That  acetylene  acted  upon  sulphuric  acid  was  first 
perceived  by  Edmund  Davy2  who  discovered  the 
hydrocarbon.  He  says  in  the  report  of  his  discovery  : 
' '  The  new  gas  is  absorbed  to  a  certain  extent  by, 
and  blackens  sulphuric  acid."  Berthelot3  first  in- 
vestigated the  products  of  the  reaction  of  strong  sul- 
phuric acid  on  acetylene.  He  obtained  an  acid,  to 


iZeits.  f.  Elect.  7,  68 1. 

2  Ann.  23,  144.     (British  Association  Reports,  1836,  62.) 

8  Ann.  Chim.  Phys.  (1863),  67,  560. 


-  10  — 

the  barium  salt  of  which  he  assigned  the  formula, 
Ba  (C2H3SO4)2,  and  called  it  barium  vinyl  sulphate. 
He  claimed  that  on  boiling  the  acid  with  water,  vinyl 
alcohol  (C2H3OH)  was  formed  as  a  decomposition 
product,  in  a  way  analogous  to  the  formation  of  ethyl 
alcohol  from  ethyl  sulphuric  acid. 

The  experiments  of  Berthelot  were  repeated  by 
Lagermarck  and  Eltekow1  and  also  by  Zeisel.2  They 
found  that  no  vinyl  alcohol  was  obtained,  but  that 
the  product  was  crotonaldehyde.  They  ascribed  the 
formation  of  the  crotonaldehyde  to  the  condensation 
of  acetaldehyde  with  sulphuric  acid  as  Kekule3  had 
shown  in  his  attempt  to  synthesize  an  aromatic  com- 
pound from  acetaldehyde.  According  to  these  in- 
vestigators the  mechanism  of  the  transformation  of 
acetaldehyde  may  be  represented  by  the  following 
reactions  : 


CH3CH  O 

CH  H2CHO  =  CH3CH:CH  CHO+H2O. 

Zeisel,  however,  ascribed  the  formation  of  the 
crotonaldehyde  which  he  found  in  his  repetition  of 
Berthelot  's  work  to  the  presence  of  vinyl  haloid  im- 
purities in  the  acetylene.  The  gas  in  all  these  ex- 
periments was  produced  from  ethylene  bromide,  or 
the  copper  acetylide,  both  of  which  give  some  vinyl 

1  Ber.  9,  637,  and  13,  693. 

2  Ann.  191,  366. 

3  Bull.  Soc.  Chim.  (177),  287,  540.     Ber.  3,  604,  and  Ber. 
2,  365. 


products.  Zeisel  claimed  that  in  some  of  his  experi- 
ments he  had  taken  special  precautions  to  eliminate 
these  impurities,  and  then  found  that  crotonaldehyde 
was  not  obtained.  When  purified  acetylene  was 
used,  a  syrupy  sulphonic  acid  was  obtained  in  small 
quantity. 

In  support  of  his  contentions  that  vinyl  alcohol  was 
obtained  from  sulphuric  acid  and  acetylene,  Berthelot 
claimed  that  allylene,  a  hornologue  of  acetylene,  gave 
allyl  alcohol  with  sulphuric  acid.  Schrohe1  showed 
that  this  was  ordinary  acetone. 

Berthelot2  next  tried  the  action  of  acetylene  on 
fuming  sulphuric  acid,  and  found  that  an  acetylene 
sulphonic  acid  was  formed  that  was  not  decomposed 
on  boiling  in  aqueous  solution.  The  salt  of  this  acid 
gave  phenol  when  fused  with  caustic  potash.  Berthe- 
lot claimed  that  acetylene  was  simultaneously  poly- 
merized and  oxidized  by  the  caustic  alkali.  Croton- 
aldehyde similarly  fused  yielded  no  phenol  but  potas- 
sium acetate. 

In  1898,  Muthman3  repeated  Berthlot's  work 
with  fuming  sulphuric  acid  and  acetylene.  He 
obtained  methionic  acid  and  explained  its  formation 
as  due  to  the  decomposition  of  an  acid  of  the  sup- 


Ae         , 
po:       formula  : 


CH(S02OH)2 


OH  _CH(S02OH) 

CH 


1  Inaug.  Dissert.  Tubingen,  1875.     Ber.  8,  367. 

2  Ann.  Chim.  Phys.  4,  XIX.,  429,  1870.     Ann.  154,   132. 

3  Ber.  31,  1880. 


—   12 


S02  +  H20. 

The  same  year  Schroeter1  published  the  results  he 
obtained  in  his  repetition  of  Berthelot's  work. 
Schroeter  was  interested  in  the  claim  that  Berthelot 
had  succeeded  in  obtaining  phenol  from  the  products 
of  the  reaction  of  acetylene  on  fuming  sulphuric  acid, 
a  synthesis  quite  remarkable  from  the  fact  that 
Kekule  had  tried  to  effect  the  condensation  of  an 
aromatic  compound  from  aldehydes  without  success. 
None  of  the  products  obtained  by  Schroeter  yielded 
phenol  when  fused  with  caustic  potash.  L,ike  Muth- 
mam  he  obtained  methionic  acid.  He  also  obtained 
the  compound  from  which  methionic  acid  was  sup- 
posed to  be  a  decomposition  product,  acetaldehyde 

CH(SOaOH)a 
disulphomc  acid,  ^^^ 

He  obtained  among  other  derivatives  its  oxime  and 
this  fact  pointed  to  the  aldehyde  formula.  There 
resulted  also  various  sulphates  of  the  above  acid  with 
complicated  formulas. 

Berthelot  repeated  his  work  and  came  to  results 
that  confirmed  his  first  conclusions.  He  obtained 
the  acetaldehyde  disulphonate  of  potassium  as  in 
Schroeter'  s  experiment.  After  the  separation  of  this 
from  the  solution,  other  compounds  of  the  formulas, 
C2H2  (S04KH)2,  (C2H2)3  (S04KH)4,  were  ob- 
tained. Examination  of  these  formulas  will  show 
that  they  are  of  the  same  empirical  composition  as 


1  Ber.  31,  2089,  and  Ann.  303,  114. 


—  13  — 

those  prepared  by  Muthman  and  Schroeter.  The 
compound  taken  by  Schroeter  for  acetaldehyde  disul- 
phonic  acid,  or  the  supposed  intermediate  product, 
H3C'CH(OSO2OH)2,  is  none  other  than  the  acid  to 
whose  salt  Berthelot  gave  the  formula,  C2H2(SO4KH)2. 
The  other  product  from  which  he  obtained  phenol, 
namely  the  compound  (C2H2)3(SO4KH)4,  may  cor- 
respond to  a  mixture  of  the  sulphates  of  acetaldehyde 
disulphonic  acid  found  by  Schroeter. 

With  dilute  sulphuric  acid,  composed  of  three  vol- 
umes of  strong  acid  and  seven  volumes  of  water,  dif- 
ferent results  were  obtained  by  Erdman1  in  1898. 
He  found  that  when  acetylene  was  passed  into  the 
boiling  acid,  acetaldehyde  was  evolved.  The  forma- 
tion of  the  aldehyde  was  increased  in  yield  by  the 
addition  of  mercuric  oxide,  and  phosphoric  acid  gave 
similar  results. 

Much  of  the  work  described  was  repeated  in  this 
laboratory  with  acetylene  generated  from  calcium 
carbide.  This  repetition  was  made  necessary  in  order 
to  understand  properly  the  reactions  that  are  to  be 
expected  when  sulphuric  acid  is  electrolyzed  with 
calcium  carbide  electrodes  in  various  strengths  of  acid. 
It  was  also  necessary  to  determine  the  behaviour  of 
calcium  carbide  towards  sulphuric  acid  of  different 
strengths. 

ACETYLENE  AND  STRONG  SULPHURIC  ACID. 

Acetylene  was  passed  into  ordinary  strong  sul- 
phuric acid  without  drying  the  gas.  When  the  color 


1  Zeits.  Anal.  Chem.  18,  (1898),  55. 


-  14- 

of  the  acid  had  become  very  dark  the  product  of  the 
absorption  was  decomposed  with  water,  and  an  aqueous 
solution  of  crotonaldehyde  was  obtained.  Pure  mono- 
hydrated  sulphuric  acid  also  yielded  crotonaldehyde. 
Fuming  sulphuric  acid,  being  saturated  with  acety- 
lene gave  no  crotonaldehyde.  The  principal  products 
were  the  sulphates  of  acetaldehyde  disulphonic  acid 
referred  to  by  Schroeter.  These  were  obtained  as  a 
brown  horny  mass  in  the  case  of  the  barium  salts. 

ACETYLENE  AND  DILUTE  SULPHURIC  ACID. 

With  sulphuric  acid  diluted  by  somewhat  more 
than  one  half  its  volume  of  water,  acetaldehyde  was 
obtained  when  the  acid  was  boiled  while  acetylene 
was  passed  into  the  flask.  The  aldehyde  was  poly- 
merized by  means  of  a  small  piece  of  phosphorus 
pentachloride  placed  in  a  Wolff  flask  connected  with 
the  receiver  of  the  distilling  apparatus. 

When  hydrogen  was  passed  together  with  the 
acetylene  into  dilute  boiling  sulphuric  acid  containing 
mercuric  oxide  in  suspension ,  thioaldehyde  was  most- 
ly polymerized  to  trithioaldehyde  It  possessed  the 
characteristic  alliaceous  odor,  and  was  obtained  as  a 
cream  colored  waxy  solid. 

The  operation  was  performed  with  a  solution  con- 
sisting of  three  parts  of  ordinary  concentrated  sul- 
phuric acid,  and  four  parts  of  water.  The  solution 
was  brought  to  its  boiling  point  in  a  flask  connected 
with  a  condenser  and  a  receiver,  while  the  two  gases 
previously  mixed  were  passed  into  the  acid.  The 
addition  of  a  few  grams  of  mercuric  oxide  to  the 


-  15  - 

solution,  resulted  in  an  increased  yield  ofthethio- 
aldehyde.  The  mercuric  oxide  added  to  the  solution 
was  first  transformed  into  sulphate,  and  this  in  turn 
was  changed  into  sulphide,  as  indicated  by  its  black 
color.  The  thioaldehyde  solidified  in  the  upper  part 
of  the  condenser  to  its  polymeric  modification,  trithio- 
aldehyde.  The  gaseous  products  of  the  reaction, 
when  passed  into  strong  ammonia  water,  formed  a 
cream  colored  precipitate  mixed  with  sulphur,  and 
possessed  an  odor  like  that  of  acetamide  and  mer- 
captan.  Thioaldehyde  and  free  sulphur  were  also 
found  in  the  distilling  flask. 

The  formation  of  the  free  aldehyde  may  be  ac- 
counted for  by  reason  of  the  catalytic  action  of  the 
mercury  salt  on  the  acetylene.  It  is  not  improbable 
that  an  intermediate  organic  mercury  compound  of 
acetylene  is  formed.  The  reactions  may  be  repre- 
sented as  follows  : 

C2H2-|-H2S  —  CH3CHS  , 

CH3. 


The  thioaldehyde  may  result  by  the  action  of  the 
hydrogen  sulphide  on  the  acetaldehyde  obtained 
from  the  action  of  the  dilute  sulphuric  acid  on  acety- 
lene in  the  presence  of  mercuric  salts. 


CH3CHO+H2S  =  CH3CHS+H20. 
Thus  Weidenbusch1  found  that  when  hydrogen  sul- 


1  Ann.  66,  158. 


—  i6  — 

phide  is  passed  into  an  aqueous  solution  of  acetalde- 
hyde,  thioaldehyde  was  obtained. 

As  I  have  obtained  crotonaldehyde  by  the  action  of 
strong  sulphuric  acid  on  acetylene  that  was  generated 
from  calcium  carbide,  it  is  evident  that  the  formation 
of  the  crotonaldehyde  is  not  due  to  vinyl  haloid 
impurities,  as  Zeisel1  maintained. 

In  order  if  possible  to  throw  some  light  on  the 
action  of  acetylene  on  sulphuric  acid,  some  of  the 
derivatives  of  the  latter  were  treated  with  acetylene. 
It  was  thought  that  some  analogous  reaction  might 
be  found  to  explain  the  varied  behaviour  of  sulphuric 
acid  itself  under  different  circumstances. 

NITROSULPHONIC  ACID  AND  ACETYLENE. 

Nitrosulphonic  acid  did  not  react  with  acetylene 
at  ordinary  temperatures.  When  the  nitrosulphonic 
acid  was  dissolved  in  pure  monohydrate  sulphuric 
acid  not  better  results  were  obtained. 

Not  only  were  no  signs  of  reaction  observed,  but 
the  acetylene  failed  to  react  with  the  sulphuric  acid, 
with  which  it  reacts  very  readily  alone.  Moreover  the 
gas  after  passing  through  the  solution  possessed  an 
ethereal  odor  as  if  it  had  been  purified  from  the  sul- 
phur compounds  that  ordinarily  give  in  its  alliaceous 
odor. 

CHI^ORSUIvPHONIC  ACID  AND  ACETYLENE. 

Chlorsulphonic  acid  was  found  to  absorb  acetylene 
very  readily  with  the  evolution  of  considerable  heat. 
The  clear  acid  became  dark-colored.  When  the 

1  Ann.  19,  366. 


—  17  — 

product  was  poured  into  water  decomposition  took 
place  quietly  and  a  black,  ill-sinelling,  viscid  mass 
settled  at  the  bottom  of  the  vessel.  Attempts  to  ob- 
tain products  pure  enough  for  analysis  did  not  suc- 
ceed. When  the  product  was  distilled  a  few  drops  of 
clear  oil  were  obtained  at  a  temperature  of  about 
100°  C.,  accompanied  by  decomposition  with  the 
separation  of  carbon  and  hydrochloric  acid.  The  oil 
possessed  the  irritating  odor  and  other  characteristics 
of  allyl  mustard  oil.  The  oil  was  decomposed  with 
long  continued  contact  with  water.  The  study  of  the 
reaction  of  acetylene  with  chlorsulphonic  acid  is 
being  continued  in  this  laboratory. 

REACTION  OF  ACETYLENE  WITH  SULPHUR  TRIOXIDE. 

Regnault,1  in  1827,  found  that  •  ethylene  united 
with  the  vapor  of  sulphur  trioxide,  and  formed  an 
anhydride  of  an  ethylene  sulphonic  acid.  To  the 

CH2-S02-0 
compound  was  ascribed  the  formula,  •  • 

CH2  —  O  —  SO2, 

and  it  was  called  carbyl  sulphate.     With  the  anhy- 

,  CH2-S02OH 
dnde  it  gave  rise  to  ethionic  acid,  • 

CH2—  O— SO  2  OH, 

and  when  this  was  boiled  with  water  it  broke  down 

CH2-OH 

into  isethiomc  acid,     •  and  sulphuric  acid. 

CH2-SO2-OH, 

From  the  investigation  of  Schroeter  on  the  action  of 
acetylene  with  sulphuric  acid,  it  became  evident  that 


1  Ann.  25,  32. 
Pogg.  Ann. 


—  i  8  — 


there  is  a  perfect  analogy  between  the  sulphonic  acids 
of  ethylene  and  acetylene.  Hthionic  acid  corre- 
sponds to  the  sulphate  of  acetaldehyde  disulphonic 

CH(SO2OH)2 
acid>  Thls  takmS  UP  water  gives 


rise  to  acetaldehyde  disulphonic  acid  itself. 

CH(S02OH)2  CH(S02OH)2 

CH(0-S02OH)2  H  4+CH(OH)2, 

or,    ^SO'°H)*  +H20. 

We  should  then  expect  that  acetylene  on  account 
of  the  greater  chemical  activity  proper  to  its  unsatur- 
ated  condition,  would  also  form  a  compound  with 
sulphuric  anhydride  analogous  to  carbyl  sulphate. 
As  acetylene  has,  however,  two  unsaturated  bonds 
more  than  ethylene,  we  may  suppose  the  union  of 
acetylene  to  take  place  in  two  ways  : 


0-O2S-CH-SO-O 
C2H2+4S08  _ 


The  first  of  these  compounds  is  the  anhydride  of 
acetaldehyde  disulphonic  acid,  the  second  is  the  an- 
hydride of  the  sulphate  of  acetaldehyde  disulphonic 
acid.  Which  of  these  is  formed  will  be  seen  when  ex- 
amining the  decomposition  products  of  the  compound 
with  water. 


—  19  — 

In  attempting  the  union  of  acetylene  with  sulphur 
trioxide,  the  crystals  from  a  strong  solution  of  fuming 
acid  were  used.  These  were  quickly  transferred  to  a 
retort  with  a  detachable  neck.  Some  phosphorus 
pentoxide  was  introduced  into  the  retort  with  the 
sulphur  trioxide  to  insure  complete  dehydration.  The 
neck  of  the  retort  was  inserted  into  a  receiver  cooled 
with  ice.  Dry  acetylene  was  passed  into  the  receiver 
until  all  the  air  was  driven  out  of  the  apparatus,  when 
the  sulphur  trioxide  was  distilled  from  the  retort  by 
gently  heating  the  latter. 

To  insure  thorough  desiccation  the  acetylene  was 
passed  through  a  wash-bottle  containing  sulphuric 
acid,  then  through  two  drying  cylinders  filled  with 
pieces  of  calcium  carbide  and  finally,  through  a  long 
tube  of  phosphorus  pentoxide.  The  exit  tube  of  the 
retort,  moreover,  was  connected  with  a  cylinder  of 
fused  calcium  chloride  so  that  in  case  air  were 
drawn  into  the  apparatus  by  reason  of  the  rapid  ab- 
sorption within,  no  moisture  would  be  admitted. 

When  the  acetylene  came  in  contact  with  the  vapor 
of  sulphur  trioxide  dense  brown-colored  fumes  ap- 
peared in  the  receiver,  and  some  heat  was  evolved. 
The  acetylene  had  to  be  passed  in  very  slowly  to 
prevent  the  union  from  taking  place  in  the  neck  of 
the  retort,  or  even  in  the  retort  itself. 

The  product  is  a  yellowish  brown  substance,  at 
first  powdery  and  apparently  amorphous,  but  soon 
collecting  on  the  sides  of  the  receiver  in  ridges  that 
made  the  glass  appear  as  if  corrugated  and  gilded 
within.  Even  under  a 'magnifying  power  of  60  to  80 
diameters  no  crystalline  structure  could  be  made  out 


-   2O  - 


with  the  microscope.  The  product  melted  at  a  moder- 
ate heat  aiid  simultaneously  decomposed  with  the 
separation  of  carbon  and  the  appearance  of  acid 
fumes.  The  compound  was  extremely  deliquescent, 
and  in  small  quantity  melted  almost  immediately  on 
exposure  to  moist  air  and  changed  to  a  dark  brown 
syrup.  The  decomposition  product  then  possessed 
the  faint  odor  of  garlic.  Water  could  not  be  directly 
added  to  the  compound,  as  it  decomposed  completely 
with  a  hissing  noise,  carbon  being  separated  and  sul- 
phuric acid  being  formed.  Sulphur  dioxide  was  also 
formed  when  the  substance  was  decomposed  with  water. 
The  acid  of  this  anhydride  was  obtained  by  exposing 
the  compound  to  moist  air  for  a  few  days,  thus  allow- 
ing it  to  absorb  water  very  gradually.  In  this  way 
the  anhydride  was  not  completely  broken  down  by 
process  of  decomposition.  After  the  substance  had  be- 
come liquified,  water  was  carefully  added  and  the 
barium  salt  obtained  by  neutralization  with  barium 
hydroxide.  The  excess  of  the  barium  sulphate  was 
filtered  off  and  the  salt  of  the  acid  remained  in  the 
solution.  No  methionic  acid  was  obtained.  Acetal- 
dehyde  disulphonic  acid  could  not  be  obtained  from 
the  solution  by  crystallization,  nor  could  the  oxime  of 
the  same  be  prepared  with  hydroxylamine.  The 
solution  contained  only  the  barium  sulphate  of  the 
acetaldehyde  disulphonic  acid  described  by  Schroeter. 
He  could  not  obtain  it  in  condition  for  analysis  owing 
to  the  variation  in  composition  of  the  salts.  Schroeter 

CH(S02OH)2 
gave  the  add  the  formula, 


The  barium  salt  could  not  be  crystallized  from  the 


-  21   - 

solution  and  when  heated  almost  to  dryness  on  a 
water  bath,  it  solidified  on  cooling  to  a  hard  horny 
brown  mass  which  could  be  removed  from  the  dish 
only  with  great  difficulty.  It  showed  no  definite 
structure,  and  could  not  be  crystallized  from  alcohol, 
or  ether,  in  either  of  which  it  did  not  seem  to  be  ap- 
preciably soluble.  As  no  acetaldehyde  disulphonic 
acid  or  even  methionic  acid  was  obtained,  but  only 
the  sulphate  of  acetaldehyde  disulphonic  acid,  it  was 
evident  from  the  decomposition  of  the  anhydride  into 
this  sulphate,  that  the  formula  of  the  product  of  the 
reaction  of  acetylene  on  sulphur  trioxide  is  to  be  rep- 

0-02S-CH-S02-02 
represented,  and    not    as 


CH  < 

I  ^2 

CHO 

The  reaction  of  the  decomposition  of  the  anhydride 
like  that  of  the  corresponding  ethylene  carbyl  sul- 
phate may  be  represented  as  follows  : 

CH2-S02-0  CH2-S02OH 


CH2  -  O  -  S02  '  CH2-0-S02OH, 

+2HOH  = 


0-02S-CH-S020 


02S-0-  CH-O-SO^ 

HO-02S-CH-S02OH  CH(S02OH)2 

HO-02S-0-CH-0-S02OH,  °r>  CH(O-SO2OH)2. 

All  compounds  of  sulphuric  acid  and  its  derivatives 
that  have  been  discovered  in  the  acetylene  series  can 
be  shown  to  be  perfectly  analogous  to  the  correspond- 
ing ethylene  compounds.  The  compound  of  acety- 


-  22 


lene  with  sulphur  trioxide  shows  by  its  decomposi- 
tion products  that  it  possesses  a  constitutional  formula 
analogous  to  ethylene  carbyl  sulphate.  The  forma- 
tion of  these  compounds  is  also  similar. 


O-O2S-CH-SO2-O 
-0^  _0_cH_o-s62. 

Ethylene  carbyl  sulphate  and  water  gives  ethionic 
acid,  and  boiled  takes  up  another  molecule  of  water 
to  form  isethionic  acid  and  sulphuric  acid.  l 

CH2-S02-0  CH2-S02OH 

CH2-0  -  SO.,  "*  CH2-0-  S 


02S-0-CH-0-S02  CH(S02OH)2 

6-O2S-CH-SO2-6  ~  CH2(O-SOaOH)2 

CH(S02OH)2         CH(S02OH)2 
-CH(OH)2,       °r'   CHO+HOH 

The  reactions  with  acetylene  and  sulphuric  acid 
derivatives  are  more  complicated  than  those  of  ethy- 
lene as  there  are  two  additional  valencies  to  be  satis- 
fied. As  a  consequence  of  loading  down  the  mole- 
cule decomposition  into  simpler  derivatives  is  to  be 
expected  whenever  it  seems  possible  to  separate  the 
stabler  elements  of  water  and  sulphuric  acid.  As  is 

1  Pogg.  Ann.  47,  509. 


seen    by   comparing    the   foregoing    reactions,    cor- 
responding to  ethionic  acid  we  have  in  the  acetylene 

.,    CH(SO2OH)a  ,  -  ,     - 

senes  the  which    is    men- 


tioned  by  Schroeter1.  Acetaldehyde  disulphonic 
acid,  the  decomposition  product,  is  the  acid  cor- 
responding to  isethionic  acid.  It  may  be  likely  that 

the  formula  of  Muthman,   CH(SO2OH)2  may  be  ap. 

CH(OH)2, 

plied  to  it  as  it  does  not  give  up  water  even  when  at- 
tempts were  made  to  crystallize  its  salts  over  phos- 
phorus pentoxide.  Its  salts  of  monovalent  metals 
contain  one  molecule  of  water  and  its  salts  of  bival- 
ent bases  contain  two  molecules  of  water  which  can 
not  be  separated  without  complete  decomposition  of 
the  compound.  The  formula  of  Schroeter  also  has 
reasons  for  its  application  because  of  the  property  of 
the  acid  to  form  an  oxime  and  other  derivatives  char- 
acteristic of  aldehydes.  As  a  further  decomposition 
product  of  both  isethionic  acid  and  acetaldehyde  disul- 
phonic acid  we  finally  have  methionic  acid. 

Bthylene  when  passed  into  fuming  sulphuric  acid 
yields  isethionic2  acid  directly,  and  acetylene  under 
the  same  conditions  gives  acetaldehyde  disulphonic 
acid. 

When  ordinary  strong  sulphuric  acid  or  an  acid 
more  or  less  hydra  ted  is  used,  none  of  the  compounds 
above  mentioned  is  formed  in  appreciable  quantity. 
There  is  nevertheless  reason  to  believe  that  here  also 


1  Ann.  303,  114. 

2  Pogg.  Ann.  XI, VII,  509. 


—  24- 

the  analogy  of  the  formation  of  the  analogous  com- 
pounds still  holds  true. 

Faraday, l  Hennel,  Regnault  and  Magnus  tried  the 
action  of  ethylene  on  sulphuric  acid  or  its  anhydride. 
Hennel  found  that  when  ethylene  is  led  into  sul- 
phuric acid  ethyl  sulphuric  acid  is  formed.  Berthelot 
repeated  the  work  of  Hennel  and  obtained  the  same 
results,  namely  ethyl  sulphuric  acid  and  alcohol. 

When  ordinary  sulphuric  acid  is  used  the  product 
differs  completely  from  that  obtained  by  the  action  of 
ethylene  on  an  acid  containing  free  sulphur  trioxide,  as 
may  be  seen  by  comparing  the  formulas  of  the  com- 
pounds in  question.  Ordinary  sulphuric  acid  with 
ethylene  gives  ethyl  sulphuric  acid,  a  metamer  of 
isethionic  acid. 

Sulphuric  Acid.          Ethyl  Sulphuric  Acid. 

HO     SQ  (C2H5)0     SQ 

HQ>S02,  HO>S°" 

Isethionic  Acid. 

C2H4(OH) 

H0>    U2> 

Ethyl  sulphuric  acid,  the  product  of  the  action  of 
ethylene  on  strong  sulphuric  acid  gives  alcohol  or 
ether  when  distilled,  according  to  the  conditions  of 
the  experiment. 

CH2  ,   HO  (C2H,)0 


1  Philosophical  Transactions,  (  1826)  240,  (  1828)  365.  Ann. 
Chim.  Phys.  XXX.,  154,  (1827).  vSee  also  Moniteur  Scien- 
tifique,  4  Ser.  XVIII.,  p.  7,  15,  21. 


—  25  — 


HO>S°2 

Berthelot  tried  to  obtain  the  alcohol  of  the  acety- 
lene series,  vinyl  alcohol.  It  was  shown  that  the 
principal,  if  not  the  only  product  of  the  action  of 
acetylene  on  sulphuric  acid,  is  crotonaldehyde.  The 
crotonaklehyde  is  the  result  of  the  condensation  of 
two  acetaldehyde  residues.  Though  a  number  of 
attempts  have  been  made  to  isolate  vinyl  alcohol1  at 
different  times,  success  has  not  as  yet  been  met  with. 
As  a  matter  of  fact  all  reactions  in  which  the  compound 
is  to  be  expected  from  its  well  known  derivatives, 
not  vinyl  alcohol  but  acetaldehyde  is  obtained.  Thus, 
for  example,  Semmler2  expected  to  obtain  vinyl 
alcohol  from  divinyl  sulphide  treated  with  silver  hy- 
droxide, but  acetaldehyde  resulted  instead. 


It  seems  that  all  the  reactions  looking  to  the  for- 
mation of  vinyl  alcohol  really  give  acetaldehyde. 
Rearrangement  of  the  molecule  takes  place  at  the 
moment  of  the  reaction.  If  vinyl  alcohol  is  really 
the  product  formed  when  acetylene  acts  on  sulphuric 
acid,  dilution  of  the  acid  is  sufficient  both  to  break 


JAnn.  Chim.    Phys.    (3),  LXVII,  6,    (1863).     Ann.  Chim. 
Phys.  (7),  XVII,  29,  7,  (1869).     Ber.  22,  2863.     Gaz.  XXIX, 

( i  ),  390- 
2  Ann.  241,  113. 


—  26  — 

up  the  compound  and  condense  the  acetaldehyde  to 
crotonaldehyde.  How  then  are  we  to  explain  the 
formation  of  the  acetaldehyde  and  crotonaldehyde 
from  the  point  of  view  that  the  reactions  of  ethylene 
and  sulphuric  acid  derivatives  and  acetylene  and  its 
derivatives  are  analogous? 

The  fact  is  that,  whether  vinyl  sulphuric  acid  be 
present  in  the  action  of  acetylene  on  dilute  or  ordinary 
concentrated  acid,  or  some  other  compound  be  formed, 
acetaldehyde  or  crotonaldehyde  is  obtained  as  the 
final  product.  It  has  been  generally  supposed  that 
acetaldehyde  simply  takes  up  the  elements  of  water, 
but  this  is  no  explanation,  and  is  in  fact  hardly  likely. 
Acetylene  and  water  do  not  unite  except  in  the 
presence  of  some  catalytic  agent,  such  as  mercury 
salts,  carbon  or  sulphuric  acid.  Two  methods  of  ex- 
planation present  themselves.  According  to  one  of 
these  we  may  suppose  the  presence  of  vinyl  sulphuric 
acid,  as  Berthelot  maintains,  according  to  the 
reaction : 

C2H2+H°-   —       (CH2:CH)0 
(CH2: 


HO 

HO     SQ 
H0>    U2, 

(CH2:CHOH)=CH3CHO. 

As  vinyl  alcohol  can  not  exist  as  such,  it  under- 
goes rearrangement  of  its  molecule  and  acetaldehyde 
is  evolved  in  dilute  solutions  of  acid.  If  the  acid  is 


_    /y  "7    _ 

strong  the  acetaldehyde  is  simultaneously  polymer- 
ized to  crotonaldehyde  : 

CH3CHO    + 

CH  H8  CHO^CH3CH:CH  CHO+H2O. 

Whatever  the  nature  of  the  hydration  of  acetylene 
it  is  evident  that  warm  diluted  sulphuric  acid  per- 
forms a  sort  of  a  catalytic  action  in  the  production  of 
aldehyde  not  unlike  the  action  of  aluminium  chloride 
in  the  chlorination  of  hydrocarbons.  At  low  temper- 
atures the  definite  compound  of  sulphuric  acid  and 
water  separates  in  crystals  of  the  composition, 
H2SO4.HOH,  which  melt  at  10.5°  C.  It  may  also  be 
likely  that  this  definite  compound  gives  up  the 
hydrogen  and  the  hydroxyl  group  to  acetylene  and 
then  takes  up  another  molecule  of  water.  When  the 
acid  becomes  of  a.  certain  dilution  acetaldehyde  ceases 
to  be  formed,  and  this  fact  would  strengthen  the 
theory.  When  the  acid  contains  little  or  no  water 
the  elements  of  water  are  abstracted  from  two  mole- 
cules of  acetaldehyde,  and  one  molecule  of  crotonal- 
dehyde  results.  The  reactions  may  be  represented 
as  follows  : 

=  CHa:CHOH-pHaS04, 
CH2:CHOH  =  CH3CHO, 

=  H2SO4-H2O. 


In  case  no  water  be  present  we  would  have  the 
reaction  : 


H2SO4'H2O. 


—  28  — 

Pure  monohydrate  sulphuric  acid  reacts  with  acety- 
lene like  ordinary  concentrated  sulphuric  acid,  and 
the  product  on  dilution  gives  crotonaldehyde  as  the 
principal  product. 

Other  substances  besides  sulphuric  acid  possess  the 
power  of  acting  as  catalytic  agents  in  oxydizing  or 
hydrating  acetylene.  Degrez1  found  that  acetylene 
is  absorbed  by  carbon,  and  when  this  was  heated  with 
water  in  closed  tubes,  acetaldehyde  was  obtained. 
The  salts  of  mercury  produce  the  same  result  when 
boiled  in  aqueous  solution  while  a  stream  of  acetylene 
was  passed  into  them.  The  yield  of  acetaldehyde 
seems  to  be  increased  in  the  presence  of  free  acid. 
In  the  last  case  the  evolution  of  the  aldehyde  is  due 
to  the  formation  and  subsequent  decomposition  of 
vinyl  or  aldehyde  derivatives  containing  mercury,  as 
will  be  shown  more  fully  in  another  paper.  These 
mercury  derivatives  are  the  intermediate  products. 
Some  have  already  been  isolated  and  their  formulas 
determined  with  accuracy,  others  will  be  described  in 
a  special  article  further  on. 

FORMATION  OF   ALDEHYDE    FROM  ACETYLENE  IN   PRESENCE 
OF  FINELY  DIVIDED  PLATINUM. 

Finely  divided  platinum  may  also  be  used  to  cause 
acetylene  to  take  up  the  elements  of  water.  When 
acetylene  is  passed  for  some  time  into  reduced  plati- 
num suspended  in  water  acidified  with  dilute  nitric 
acid,  aldehyde  is  formed.  The  product  is  allowed  to 
stand  by  itself  for  some  time  in  order  to  permit  all 
the  acetylene  in  solution  to  change  into  aldehyde. 


1  Bull.  Soc,  Ch.  XI,  362. 


-  29  — 

The  odor  of  the  gas  disappears  and  that  of  acetalde- 
hyde  becomes  very  noticeable.  The  product  is  filtered 
and  the  filtrate  treated  with  iodine  and  caustic  potash 
to  an  alkaline  reaction  when  an  abundant  precipitate 
of  iodoform  is  obtained.  When  the  suspended  plati- 
num is  acidified  with  hydrochloric  acid  no  aldehyde 
is  obtained.  Similar  results  could  not  be  obtained  in 
alkaline  solutions  in  which  reduced  cobalt  was  sus- 
pended. 

Acetylene  shows  the  general  tendency  to  form 
aldehyde  derivatives  and  behaves  like  acetaldehyde 
itself  in  many  reactions.  Towards  sulphuric  acid  the 
action  of  acetylene  and  acetaidehyde  is  exactly  simi- 
lar. Weidenbusch1  first  noticed  that  acetaldehyde 
was  absorbed  by  sulphuric  acid,  but  he  threw  no  light 
on  the  nature  of  the  reaction  that  takes  place.  He 
simply  stated  that  the  acid. became  dark-colored  when 
aldehyde  was  passed  through  it. 

Delepine2  found  that  ordinary  aldehyde  gave  defi- 
nite products  with  strong 'sulphuric  acid.  The  latter 
yielded  as  a  product  of  reaction  the  same  compounds 
as  were  obtained  by  Schroeter  by  the  action  of  acety- 
lene on  the  acid  under  the  same  conditions.  Acetal- 
dehyde disulphouic  acid  and  methionic  acid  were 
obtained.  With  ordinary  strong  sulphuric  acid 
crotonaldehyde  resulted  on  dilution  of  the  product, 
as  Kekule  had  found  before.  This  is  likewise  the 
product  obtained  from  the  action  of  acetylene  upon 
sulphuric  acid  as  L,agermarck  and  Kltekow,  and 


1  Ann.  66,  155. 

2  Compt.  Rend.  133,  875. 


-3o- 

Zeisel  have  shown.  Other  derivatives  of  acetalde- 
hyde,  such  as  acetamide  and  chloral  also  give  rise  to 
acetaldehyde  disulphonic  acid  when  treated  with  fum- 
ing sulphuric  acid.  In  summing  up  the  results  we 
may  conclude  that  the  analogy  of  the  reactions  be- 
tween acetylene  and  ethylene  in  their  behaviour 
towards  sulphuric  acid  generally  holds  true. 

i. —  Acetylene  in  dilute  boiling  solutions  of  sul- 
phuric acid  is  oxydized  to  vinyl  alcohol  and  this  by 
intramolecular  rearrangement  becomes  acetaldehyde. 
It  is  probable  that  a  vinyl  compound  is  first  formed 
which  being  very  unstable  breaks  down  into  the 
other  compounds  just  mentioned. 

2. —  In  the  presence  of  strong  sulphuric  the  acet- 
aldehyde supposed  to  be  formed  is  condensed  to 
crotonaldehyde  with  the  separation  of  water  ;  ordinary 
alcohol  heated  with  concentrated  sulphuric  acid  also 
loses  water  and  is  changed  to  ether. 

3. — With  fuming  sulphuric  acid  the  derivatives  of 
acetylene  are  perfectly  analogous  to  those  of  ethylene, 
being  the  sulphonic  acids  of  ethylene  and  acetylene 
as  already  mentioned. 

4. — Sulphur  trioxide  gives  an  anhydride  with  acety- 
lene similar  to  the  ethylene  compound.  It  decom- 
poses with  the  addition  of  water  into  the  sulphate  of 
acetaldehyde  disulphonic  acid,  which  is  analogous  to 
ethionic  acid  in  the  ethylene  series.  Further  decom- 
position changes  this  sulphate  into  acetaldehyde 
disulphonic  acid  which  is  analogous  to  isethionic  acid 
the  compound  similarily  obtained  from  ethionic  acid. 


f 


THE  ACTION  OF  SULPHURIC  ACID  ON  CALCIUM 
CARBIDE 

The  behaviour  of  sulphuric  acid  toward  calcium 
carbide  varies  according  to  the  conditions  under  which 
the  experiment  is  carried  on,  such  as  temperature  of 
the  operation,  the  strength  of  the  acid  used,  and  the 
degree  of  fineness  of  the  calcium  carbide  employed. 
Dilute  sulphuric  acid  differs  little  in  its  action  on 
carbide  from  water.  The  water  present  decomposes 
the  carbide  and  calcium  sulphate  results  by  the 
further  action  of  the  acid. 

i.  —  Whenever  the  action  of  a  compound  with  cal- 
cium carbide  is  very  rapid  much  heat  is  given  off  by 
reason  of  the  endothermic  nature  of  the  compound 
and  very  often  total  decomposition  takes  place. 
When  concentrated  sulphuric  acid  is  allowed  to  drop 
on  pieces  of  calcium  carbide  the  size  of  a  pea,  or  when 
powdered  carbide  be  thrown  into  strong  sulphuric 
acid  this  total  decomposition  takes  place  without  the 
application  of  external  heat.  In  general  when  finely 
divided  carbide  is  used  the  breaking  down  of  the  acid 
and  the  separation  of  carbon  can  only  be  prevented 
by  cooling  the  acid  in  a  freezing  mixture  or  throwing 
pieces  of  ice  into  the  acid. 

In  an  experiment  performed  a  flask  of  five 
litres  capacity  was  used  and  a  mixture  of  about 
one  hundred  grams  of  granulated  and  powdered 
calcium  carbide  was  put  into  it.  From  a  drop- 
ping funnel  strong  sulphuric  acid  was  allowed 
to  fall  upon  the  mixture.  The  first  drop  caused  a 
strong  evolution  of  vapors,  the  violence  of  the  reac- 
tion increasing  as  more  heat  was  evolved.  The  gases 


-32- 

were  passed  through  a  well  cooled  receiver.  The 
mass  of  the  carbide  became  brown,  and  finally  much 
carbon  separated.  Sulphur  dioxide,  hydrogen  sul- 
phide, acetylene  and  carbon  dioxide  were  given  off. 
By  far  the  greater  portion  of  the  gas  consisted  of 
sulphur  dioxide  and  acetylene.  Hydrogen  sulphide 
was  present  in  great  quantity,  especially  at  the  be- 
ginning of  the  operation  and  later  on  it  ceased  to  be 
formed.  I^ead  acetate  gave  at  first  a  black  precipitate 
of  the  sulphide  but  later  only  the  sulphite  was  ob- 
tained. The  acetylene  was  determined  by  absorption 
with  silver  nitrate  in  ammoniacal  solution.  The 
residue  in  the  flask  consisted  of  a  dirty  black  mass 
composed  principally  of  calcium  and  magnesium  sul- 
phates and  carbon.  When  the  decomposition  was 
carried  on  while  heating  the  acid  in  the  flask  and 
allowing  calcium  carbide  slowly  to  fall  into  the  acid 
the  action  was  more  violent  but  no  different  results 
were  obtained. 

2. —  Powdered  and  granulated  carbide  was  added  to 
strong  sulphuric  acid  cooled  in  ice-water.  Decom- 
position took  place  slowly  and  the  action  could  not 
be  well  regulated.  Acetylene  was  evolved  with  some 
hydrogen  sulphide,  sulphur  dioxide  came  off  when 
the  action  became  uncontrollable.  Constant  stirring 
was  necessary  to  prevent  this  complete  decomposition 
with  the  evolution  of  sulphur  dioxide.  The  mass  did 
not  become  brown  but  calcium  sulphate  was  precipi- 
tated and  the  mixture  became  a  pasty  consistency. 
The  odor  of  hydrogen  sulphide  was  only  noticed  after 
standing  for  some  days.  Neither  aldehyde  or  croton- 
aldehyde  could  be  noticed.  The  characteristic  odor 


-33- 

of  thioaldehyde  was  present  when  the  mixture  was 
diluted. 

3.  —  When  acid  more  dilute  was  used,  for  example, 
of  specific  gravity  1.75,  or  when  strong  acid  was 
allowed  to  stand  uncovered  so  that  moisture  could  be 
absorbed  from  the  atmosphere,  a  precipitate  soon 
occurred,  decomposition  took  place  slowly,  and  hydro- 
gen sulphide  was  evolved  with  the  acetylene.  After  a 
few  days  the  strong  odor  of  thioaldehyde  was  noticed. 
The  thick  emulsion  was  somewhat  diluted  with  water, 
put  into  a  large  flask  and  carefully  heated  to  the 
boiling  point.  The  distillate  contained  not  even  traces 
of  either  acetaldehyde  or  crotonaldehyde.  The  thioal- 
dehyde heated  in  an  acid  solution  was  polymerized  to 
parathioaldehyde  which  was  precipitated  as  a  yellow 
waxen  mass  in  the  cooler  parts  of  the  condenser. 
The  thioaldehyde  was  supposed  to  result  either  from 
the  action  of  the  nascent  acetylene  on  hydrogen  sul- 
phide, or  from  the  action  of  hydrogen  sulphide  on 
ordinary  aldehyde.  A  mixture  of  iron  sulphide  and 
carbide  gave  an  increased  yield  of  the  thioaldehyde 
when  treated  with  acid  of  the  same  concentration. 

In  the  experiments  just  described  the  solu- 
tion was  carefully  examined  for  organic  salts. 
Only  the  faintest  traces  of  formic  acid  were  found. 
Magnesium  sulphate  was  found  in  quantity,  neither 
acetaldehyde  disulphonic  acid  or  methionic  acid  could 
be  detected  in  their  salts,  nor  any  of  the  compounds 
mentioned  by  Schroeter.  To  make  sure  that  none  of 
these  products  if  present  might  escape  observation, 
the  calcium  salts  of  the  filtrate  were  changed  into 
the  barium  zinc  and  other  metallic  compounds  but 


-  34  — 

no  organic  substances  were  found  in  appreciable 
quantity,  though  large  amounts  of  material  were  re- 
peatedly employed.  The  magnesium  sulphate  was 
mixed  with  some  tarry  impurities  when  evaporated 
to  dryness  but  even  here  only  traces  of  organic  mat- 
ter were  shown  by  ignition.  Repetitions  of  these 
attempts  gave  the  same  results ;  a  trace  of  formic 
acid  and  parathioaldehyde. 

4.  —  The  action  of  calcium  carbide  on  stronger  acid 
of  specific  gravity  1.82  to  1.84  gave  by  slow  action 
quite  different  results  at  ordinary  temperatures. 
Four  or  five  liters  of  this  acid  were  poured  into  a 
beaker  and  several  large  pieces  of  calcium  carbide 
were  immersed  in  the  acid  so  as  to  be  completely 
covered.  The  beaker  was  placed  in  a  stronger  ves- 
sel to  guard  against  the  evil  results  of  breakage,  and 
was  carefully  covered  to  prevent  the  absorption  of 
water  from  the  atmosphere.  The  action  was  very 
slow,  and  in  winter  weather  would  continue  a  month 
before  evident  results  could  be  obtained  from  a  test- 
portion  diluted  with  water.  In  the  summer  and  in 
direct  sunlight  a  few  days  were  sufficient  to  bring  out 
decided  results  and  the  acid  began  to  take  on  a  choco- 
late color.  At  first  the  carbide  steadily  gave  off 
small  bubbles,  and  a  faint  sweet  smell  mixed  with  the 
odor  of  sulphur  dioxide  was  evolved.  For  some  time 
the  calcium  carbide  presented  a  clean  surface  to  the 
acid  as  the  calcium  sulphate  was  dissolved  to  a  clear 
solution.  On  the  whole  the  evolution  of  gas  was  ex- 
tremely slow.  After  a  while  the  excess  of  sulphate 
could  no  longer  be  held  in  solution  and  the  acid  be- 
came viscid  and  muddy.  During  the  process  the 


—  35  — 

solution  was  frequently  stirred,  yet  care  had  to  be 
taken  not  to  move  about  the  pieces  of  carbide  too 
violently  as  a  series  of  surface  explosions  occurred 
when  the  carbide  was  rubbed  gently  with  a  glass 
rod  These  small  detonations  were  like  the  explos- 
ion of  a  percussion  cap  and  were  accompanied  with 
the  appearance  of  a  flash  of  bright  light.  A  gas  was 
given  off  which  on  coming  in  contact  with  the  air 
gave  a  small  cloud  of  smoke.  When  the  carbide  was 
moved  over  the  bottom  of  the  vessel  a  continuous 
rattle  of  these  minute  explosions  was  obtained  and 
the  flash  of  flame  was  at  times  two  centimeters  in 
length.  This  phenomenon  occurred  as  long  as  the 
surface  of  the  carbide  was  kept  from  the  sediment  of 
calcium  sulphate.  The  explosions  did  not  occur  on 
the  whole  surface  of  the  carbide,  but  principally  at 
metallic  looking  nodules.  Sharp  edges  gave  the 
explosions  very  energetically.  The  phenomenon 
might  be  due  to  minute  pieces  of  free  calcium,  to  cal- 
cium phosphide  giving  off  phosphine,  or  to  silicon 
compounds  giving  off  silicon  hydride.  The  explos- 
ions never  occurred  unless  the  carbide  was  rubbed  or 
moved.  They  have  not  been  known  to  take  place 
spontaneously. 

When  the  pasty  mass,  the  product  of  the  experi- 
ment just  referred  to,  was  poured  into  cold  water, 
the  strong  odor  of  crotonaldehyde  was  given  off  and 
calcium  sulphate  was  immediately  precipitated.  Up- 
on subjecting  the  decomposed  mixture  to  distillation, 
vapors  passed  over  with  some  water  at  a  temperature 
below  100°  C.  The  distillate  possessed  the  odor  and 
the  other  characteristics  of  crotonaldehyde  as  described 


-36- 

by  Kekule1.  The  crotonaldehyde  was  oxydized  to 
crotonic  acid  by  means  of  silver  hydroxide.  A  bright 
silver  mirror  was  obtained  acccording  to  the  reaction  : 

2CH3CH:CHCHO+3Ag20  = 
2CH8CH:  CHCOOAg+H20+4Ag. 

After  filtering  off  the  excess  of  the  silver  oxide, 
the  solution  was  heated  on  a  hot  water  bath  to  obtain 
the  silver  salt,  but  decomposition  set  in.  The  vapors 
evolved  possessed  a  rancid  odor  and  a  dark-colored 
precipitate  was  left  in  rings  on  the  dish  as  the  water 
evaporated.  As  the  silver  salt  could  not  be  obtained 
it  was  changed  into  the  barium  salt  with  barium  car- 
bonate. The  barium  salt  crystallized  from  water  in 
small  cubes. 

Part  of  the  distillate  was  treated  with  sodium  car- 
bonate and  iodine  and  on  warming  an  abundant  pre- 
cipitate of  iodoform  was  obtained.  The  crystals  were 
filtered  and  their  melting  point  found  to  be  119°  C. 
The  product  was  pure  iodoform.  Reduction  with 
zinc  dust  gave  the  nauseating  odor  of  butyric 
alcohol. 

5.  —  Monohydrated  sulphuric  acid  was  also  treated 
with  calcium  carbide  in  the  same  manner  as 
described  for  sulphuric  acid.  The  action  was  more 
rapid,  and  cooling  had  to  be  applied  to  prevent  com- 
plete decomposition  of  the  acid.  In  a  few  hours  the 
action  was  almost  completed.  The  acid  became  so 
pasty  that  the  contents  could  not  be  poured  from  the 
vessel.  Similar  results  were  obtained  as  in  the  pre- 
ceding experiment,  but  the  yield  of  crotonaldehyde 

1  Ann.  162,  et  Seq. 


OF  THE 

UNIVERSITY   } 
—  37  F — 

^jLTTiRK '••.>/ 

was  much  better  in  proportion  to  the  amount  of  the 
acid  used. 

ELECTROLYSIS    OF    VARIOUS    SOLUTIONS    WITH    CAL- 
CIUM CARBIDE  ELECTRODES. 

Before  entering  upon  the  course  of  experiments,  I 
shall  detail  some  of  the  methods  used  in  the  analysis 
of  the  gaseous  products,  as  most  attention  was  paid 
to  the  volatile  products  that  were  formed.  Consid- 
erable difficulty  was  experienced  in  the  separation 
and  analysis  of  the  gases  formed.  Though  it  is  easy 
to  obtain  absorbents  for  the  individual  gases,  their 
complete  elimination  and  separation  is  in  some  cases 
a  very  tedious  operation,  and  often  the  separation 
volumetrically  was  found  to  be  impossible. 

Ammoniacal  cuprous  chloride  has  been  used  as  an 
absorbent  for  acetylene,  but  as  it  dissolves  indefinite 
amounts  of  ethylene  according  to  the  concentration 
of  the  solution  of  the  absorbent,  it  can  not  be  used 
without  modification  of  the  method.  The  separation 
of  acetylene  from  sulphur  gases  is  very  difficult  vol- 
umetrically. No  absorbent  has  been  found  that  will 
perfectly  and  quickly  separate  sulphur  gases  without 
affecting  the  ethylene  and  acetylene  present.  The 
method  of  Berge  and  Reychler1  for  the  purification  of 
the  acetylene  though  it  may  remove  all  phosphine, 
nevertheless  dissolves  large  amounts  of  the  hydro- 
carbon with  the  formation  of  definite  mercury  com- 
pounds. The  authors  claim  that  the  solution  can  be 
used  for  quantitative  separation  of  the  gases,  and 


Soc.  Chim.  Ill,  XVII,  218,  (1897). 


-38- 

recommend  a  solution  consisting  of  eighty  parts  of 
water,  twenty  of  hydrochloric  acid  and  eight  of  mer- 
curic chloride.  The  gas  is  first  passed  through  caus- 
tic potash,  where  the  sulphur  gases  and  carbon 
dioxide  are  removed.  Hydrogen  sulphide  is  changed 
to  sulphate  in  the  potash  solution.  Phosphorus  is 
changed  to  phosphate  and  determined  gravimetrically 
by  the  method  of  Sonnenschein.  I  have  tested  the 
purifying  agent  of  Berge  and  Reychler  to  see  if  it 
could  be  used  volumetrically,  but  negative  results 
were  obtained.  In  the  first  place  hydrogen  sulphide 
is  not  perfectly  absorbed  by  caustic  potash  as  was 
found  by  test  experiments  on  known  volumes  of 
gases.  Moreover,  the  potash  solution  holds  acetylene 
gas  in  solution  in  varying  proportions  according  to 
the  concentration.  If  the  caustic  solution  be  previ- 
ously saturated  with  acetylene  the  difficulty  is  not 
overcome.  Unreliable  variations  occur.  Lead  acet- 
ate will  take  up  all  the  hydrogen  sulphide,  but  acet- 
ylene is  also  absorbed,  and  the  quantities  taken  up 
vary. 

Although  the  absorbent  of  Berge  and  Reychler  does 
not  precipitate  acetylene  the  gas  is  nevertheless  dis- 
solved with  the  formation  of  definite  compounds,  as 
was  shown  by  Biginelli.1  I  have  found  that  ninety- 
five  per  cent,  of  the  gas  is  taken  up  by  the  reagent. 
It  can  not  then  be  used  in  the  Hempel  absorption 
apparatus.  If  the  solution  be  previously  saturated 
with  the  gas,  the  absorbent  can  not  be  relied  on  as  it 
gives  erratic  results.  It  has  accordingly  been  found 


1  Ann.  di  Farm,  e  Chim.  (1898 ),  16.     Cent.  ( 1898  ),  925. 


-  39- 

necessary  to  omit  the  elimination  of  the  phosphine. 
At  all  events  the  traces  are  quite  faint  and  would  not 
tend  to  influence  the  results  of  the  experiments 
appreciably. 

The  various  constituents  of  the  gaseous  product 
were  successively  taken  out  by  their  proper  absorbents 
and  the  apparatus  used  for  the  analysis  was  of  the 
type  introduced  by  Hempel  For  the  elimination  of 
the  acetylene,  however,  the  Bunte-Seger  apparatus 
was  used  in  connection  with  the  Hempel  burettes  and 
pipettes. 

The  substances  liable  to  be  met  with  in  this  work 
are  somewhat  limited  and  consist  principally  of 
acetylene,  ethylene,  ethane,  oxygen,  carbon  dioxide 
and  carbon  monoxide,  traces  of  sulphur  dioxide  and 
hydrogen  sulphide.  Ammonia  and  oxides  of  nitro- 
gen are  to  be  met  with.  Sulphur  dioxide  was 
generally  found  in  such  small  quantities  as  to  be  neg- 
ligible. The  gas  mixture  was  in  every  case  left  to 
stand  over  water  for  some  time  in  order  to  allow 
gases  soluble  in  water  to  be  taken  out.  Acetylene 
was  in  every  instance  taken  out  first  because  of  the 
quantity  present  and  because  it  is  taken  in  solution 
by  nearly  all  of  the  other  absorbents  in  greater  or  less 
degree.  The  absorption  was  made  by  the  method 
described  by  Moody  and  Tucker.2  The  authors  found 
that  an  ammoniacal  solution  of  silver  salt  is  the  best 
absorbent  for  separating  acetylene  from  ethylene 
volumetrically.  To  a  solution  of  silver  nitrate  hydro- 
chloric acid  is  added  until  an  acid  reaction  is  obtained. 


'Jour.  Amer.  Chem.  Soc.  23,  671. 


-  40- 

Ammouia  water  is  then  added  until  the  reaction  is 
just  alkaline.  This  was  found  to  be  a  better  solution 
than  arnmonical  cuprous  chloride  which  absorbs  large 
quantities  of  ethylene.  The  gas  can  be  regained, 
however,  on  boiling  the  cuprous  chloride  solution  as 
Berthelot1  described  but  the  method  is  longer  and 
more  tedious.  I  have  examined  Moody  and  Tucker's 
reagent  with  known  mixtures  of  the  two  gases. 
Though  it  is  not  as  sensitive  to  small  quantities  of 
acetylene  as  ammoniacal  cuprous  chloride,  and  though 
the  last  traces  of  the  gas  can  be  eliminated  only  after 
a  long  absorption,  the  use  of  the  Bunte-Seger  appar- 
atus effects  the  completion  of  the  operation  in  a  very 
short  time. 

The  ethylene  is  separated  in  the  usual  manner  over 
fuming  sulphuric  acid  containing  crystals  of  sulphur 
trioxide.  Hydrogen  was  taken  out  by  means  of 
palladium  as  described  in  the  manuals  of  gas  analysis. 
The  ethane  was  determined  by  explosion  after  the 
hydrogen  had  been  removed.  It  was  also  calculated 
by  silent  combustion  in  a  Winckler's  pipette  with 
incandescent  platinum  spiral.  Of  the  anode  products 
carbon  dioxide  was  quickly  removed  in  the  caustic 
potash  pipette.  Acetylene  was  next  taken  out  and 
then  oxygen  with  the  phosphorus  pipette. 

ELECTROLYSIS   OF   SULPHURIC    ACID  WITH   CALCIUM  CARBIDE 

ELECTRODES. 
(PRELIMINARY   EXPERIMENT.) 

Before  the  operation  described  by  Harris2  had  come 


1  Ann.  Chim.  Phys.  3,  LXVII,  57,  (  1863  ). 

2  Electrochemical  Industry,  p.  131,  (Vol.  i.  )  No.  4,  (Dec. 
1902  ). 


41 

to  my  notice  experiments  somewhat  similar  had  al- 
ready been  made  in  this  laboratory.  The  object  of 
the  work  was  to  effect  results  such  as  those  mentioned 
by  the  author,  namely  to  obtain  alcohol  or  ether  from 
acetylene  by  means  of  electrolysis.  Instead,  how- 
ever, of  passing  acetylene  into  heated  sulphuric  acid, 
one  or  two  soluble  electrodes  of  calcium  carbide  were 
used.  At  the  carbide  cathode  the  hydrogen  ions 
would  come  in  contact  with  nascent  acetylene  slowly 
given  off  by  the  electrode  which  reacted  with  the 
acid  or  rather  with  the  water  in  the  sulphuric  acid. 
The  first  experiment  was  conducted  with  no  other 
end  than  to  obtain  qualitative  results.  It  was  ex- 
pected that  the  ethylene  uniting  with  the  sulphuric 
acid  would  form  ethyl  sulphuric  acid  and  that  ether 
or  alcohol  would  be  obtained  from  this  on  diluting  or 
distilling  the  product.  The  distillate  gave  the  iodo- 
form  test  unmistakably,  in  fact  it  was  possible  to  ob- 
tain considerable  quantities  of  the  latter  compound. 
To  be  sure  that  the  iodoform  was  really  due  to  alco- 
hol, the  experiments  already  referred  to,  or  the  action 
of  acetylene  on  sulphuric  acid,  were  undertaken.  It 
was  found  that  iodoform  was  obtained  even  when  no 
current  had  been  used,  both  when  acetylene  was 
allowed  to  act  on  sulphuric  acid,  and  when  calcium 
carbide  was  allowed  to  react  with  stronger  sulphuric 
acid.  As,  however,  the  iodoform  test  does  not  prove 
conclusively  the  presence  of  alcohol,  it  will  be  neces- 
sary to  obtain  and  analyze  alcohol  as  such.  If  the 
ethylene  which  is  present  previous  to  the  formation 
of  ethyl  sulphuric  acid,  be  collected  and  analyzed,  we 
may  conclude  that  the  iodoform  test  was  obtained  at 


-42- 

least     partly    from   the   alcohol   that    was    formed. 

Principally  the  gaseous  products  of  the  experiments 
will  be  examined  in  order  to  arrive  at  definite  con- 
clusions as  to  the  presence  of  alohol.  I  shall  now 
describe  some  of  the  experiments  performed  in  the 
electrolysis  of  sulphuric  acid  with  calcium  carbide 
electrodes. 

In  the  preliminary  experiments  the  apparatus  used 
is  represented  in  figure  (  i  ).  A  well-shaped  piece  of  cal- 
cium carbide  was  chosen  for  each  electrode.  A  hole 
about  one  half  a  centimeter  in  diameter  was  bored 
into  one  end  with  a  steel  drill,  and  a  copper  wire  was 
fastened  into  this  with  melted  lead.  The  electrodes 
were  contained  in  porous  cups  in  order  to  examine 
separately  the  products  of  reaction  at  each  pole. 
Each  porous  cup  was  closed  with  a  stopper  through 
which  a  Wurtz  tube  was  passed.  The  electrical  con- 
nections with  the  poles  were  made  through  the  corks 
of  the  Wurtz  tubes,  while  the  gas  was  conducted 
through  the  side  tubes  into  separate  gasometers. 
The  electrodes  dipped  only  partly  below  the  surface 
of  the  acid  in  each  cup,  and  the  operation  of  elec- 
trolysis was  carried  on  in  a  large  thick  walled  vessel. 
The  thermometer  in  the  vessel  registered  the  tem- 
perature during  the  experiment. 

In  dilute  solutions  of  sulphuric  acid  acetaldehyde 
is  present  at  least  when  heated.  At  the  anode  simul- 
taneously with  the  oxidation  of  acetylene  to  carbon 
dioxide  and  water,  aldehydes  might  become  acids. 
At  the  cathode,  reduction  of  aldehyde  would  take 
place  to  form  alcohol.  Acetylene  might  likewise  be 
changed  to  ethylene  with  the  subsequent  formation 


—  43  — 


-44- 

of  ethyl  sulphuric  acid.  It  remains  then  to  be  found 
out  whether  the  actual  results  in  the  experiments  to 
be  described  correspond  to  the  expectations  enter- 
tained in  regard  to  the  formation  of  the  compounds 
enumerated. 

Calcium  carbide  has  been  found  to  conduct  elec- 
tricity to  a  considerable  extent,  though  compared  to 
the  metals  it  has  a  low  conductivity.  This  great 
resistance  to  the  current  is  one  of  the  principal  diffi- 
culties to  be  contended  with  in  using  this  substance 
as  an  electrode.  Owing  to  the  great  electromotive 
force  that  must  be  used,  the  calcium  carbide  becomes 
very  much  heated.  If  the  contact  is  not  very  good 
the  copper  wires  at  this  point  are  often  melted. 

In  cold  concentrated  aqueous  solutions  of  some 
salts,  calcium  carbide  is  very  stable.  Concentrated 
sulphuric  acid  attacks  it  very  slowly,  and  it  is  gen- 
erally necessary  to  add  water  in  order  to  increase  the 
evolution  of  gas.  Concentrated  calcium  chloride  and 
calcium  nitrate  solution  are  almost  without  any 
action  upon  calcium  carbide,  and  must  in  neutral 
solution  be  diluted  with  even  more  water  than  sul- 
phuric acid.  Zinc  chloride  and  sodium  hyposulphite 
must  also  be  diluted  when  concentrated  solutions  are 
used.  It  was  thought  advisable  to  use  these  solu- 
tions of  salts  in  order  to  obtain  decisive  results  as  to 
the  presence  of  ethylene,  in  the  electrolysis  of  elec- 
trolytes with  calcium  carbide  cathode. 

I  have  already  referred  to  electrolysis  in  the 
presence  of  acetylene  gas  in  solution  in  the  electro- 
lyte. I  have  not  been  able  to  find  that  any  attempt 
was  made  to  use  calcium  carbide  as  a  soluble  electrode 


—  45  - 

giving  off  nascent  acetylene.  We  should  expect  that 
if  an  electrolytic  synthesis  were  likely  to  take  place 
it  ought  to  occur  where  the  constituents  are  present 
in  the  nascent  state.  If  hydrogen  unites  to  acetylene 
to  form  ethylene,  as  Wilde  and  Berthelot  have  shown, 
we  should  expect  the  same  result  at  the  cathode  of 
calcium  carbide.  The  ethylene  thus  formed  in  sul- 
phuric acid  solution  would  unite  with  the  acid  to  form 
ethyl  sulphuric  acid.  This  at  the  proper  temperature 
would  give  off  ether  and  alcohol  according  to  the 
conditions  of  dilution  or  concentration.  It  would  be 
simply  necessary  to  maintain  in  the  solution  of  acid 
the  proper  proportion  of  water.  The  action  was  ex- 
pected to  take  place  as  follows  : 

4*  H20  ±=  CaSO4+  C2H2+  H2O, 


H2SO4=2H-fSO4,  or  H+HSO4, 


During  the  subsequent  experiments  the  current 
used  in  the  electrolysis  was  obtained  from  a  storage 
battery  of  fifty  cells.  A  voltmeter  and  amperemeter 
registered  accurately  the  constants  of  the  current. 
For  the  experiment  in  question  an  electromotive  force 


-46- 

of  one  hundred  volts  was  used.  The  electrolyte  was 
ordinary  concentrated  sulphuric  acid  somewhat  dilut- 
ed during  the  experiment  in  order  to  obtain  a  suit- 
able flow  of  gas  before  turning  on  the  current.  On 
turning  on  the  switch  an  immediate  increase  of  the 
flow  of  gas  was  noted.  After  the  operation  had  been 
allowed  to  continue  for  some  time  to  drive  the  air  out 
of  the  apparatus,  and  also  to  obtain  normal  condi- 
tions of  experiment,  the  gas  was  collected  in  separ- 
ate gasometers  from  both  poles  simultaneously.  The 
reaction  was  continued  for  more  than  three  hours, 
during  which  a  considerable  rise  of  temperature 
occurred,  and  the  acid  began  to  take  on  a  brown 
color  both  in  the  cups  and  in  the  solution  outside  of 
the  cups.  The  average  temperature  was  noted  at 
different  stages  of  the  operation.  The  greatest  rise 
was  noted  in  the  path  of  the  current,  being  about  70° 
to  71°  C. 

Sulphur  dioxide  was  given  off  in  small  quantity  as 
the  acid  was  decomposed.  This  occurred  principally 
at  the  cathode  where  the  reduction  takes  place.  After 
the  experiment  the  cathode  was  found  to  be  very 
little  changed,  though  covered  with  a  dark  slimy 
sediment.  The  anode  was  blackened  and  eaten  away, 
as  if  the  acetylene  had  been  completely  decomposed 
with  the  separation  of  carbon.  After  standing  for 
some  time  the  contents  of  the  porous  cups  were 
separately  analyzed,  and  the  gases  from  the  separate 
poles  were  examined.  Of  the  56.6  ccm.  of  the  gas 
obtained  at  the  anode  only  7  ccm.  were  found  to  be 
acetylene.  No  ethylene  resulted.  No  trace  of  alco- 
hol or  ether  was  found.  On  decomposing  the  con- 


—  47- 

tents  of  the  porous  cups  with  water  an  ethereal  odor 
was  noticed,  and  when  the  product  was  distilled  a 
volatile  compound  passed  over  with  water  vapor  be- 
fore the  thermometer  registered  100°  C.  The  distillate 
possessed  the  odor  of  crotonaldehyde,  and  gave  a 
voluminous  precipitate  of  iodoforin  with  sodium  car- 
bonate and  iodine.  The  product  showed  all  the 
characteristics  of  crotonaldehyde.  It  was  oxidized  to 
crotonic  acid  by  freshly  precipitated  silver  oxide.  A 
salt  was  obtained  that  could  not  be  evaporated  on  the 
water  bath  without  decomposition.  During  the 
breaking  down  of  the  compound  the  fumes  given  off 
possessed  the  rancid  odor  of  butyric  acid.  The  iodo- 
forrn  obtained  was  filtered,  dried  and  purified  by 
crystallization.  It  melted  at  U9°C.  exactly.  Con- 
sidering the  small  amount  of  acid  decomposed  the 
yield  of  iodoform  was  considerable.  The  mirror  test 
for  aldehyde  was  also  obtained.  It  would  be  incon- 
clusive to  maintain  that  the  iodoform  test  was  due  to 
tha  presence  of  alcohol  since  the  product  of  distillation 
gave  an  aldehyde  reaction  and  possessed  none  of  the 
other  characteristics  of  ethyl  alcohol.  Moreover  as 
L,ieben  has  shown  aldehydes  give  the  iodoform  reac- 
tion far  more  readily  than  ethyl  alcohol.  As  the 
gaseous  product  gave  no  trace  of  ethylene  it  seemed 
evident  that  the  current  might  not  have  effected  the 
union  of  nascent  hydrogen  with  nascent  acetylene.  In 
order  to  establish  with  certainty  whether  acetylene 
could  be  united  with  nascent  hydrogen  at  the  cathode 
of  calcium  carbide  an  extended  series  of  experiments 
was  undertaken  with  various  electrolytes  with  which 
ethylene  does  not  form  a  compound.  If  the  product 


-48- 

of  the  electrolysis  of  dissolved  acetylene  in  sulphuric 
acid  solutions  be  really  alcohol  then  by  using  an 
electrolyte  that  does  not  absorb  ethylene  the  gas  can 
be  estimated  volumetrically  by  the  methods  of  gas 
analysis. 

ELECTROLYSIS   OF   DILUTE  SULPHURIC    ACID    WITH    CALCIUM 
CARBIDE  ELECTRODES. 

As  dilute  sulphuric  acid  does  not  readily  absorb 
ethylene  attempts  were  made  to  obtain  the  free  gas 
by  electrolyzing  the  dilute  acid.  In  performing  the 
operation  some  difficulty  was  experienced.  When 
the  acid  was  too  dilute  the  carbide  was  rapidly  eaten 
away  and  a  layer  of  calcium  sulphate  was  formed  on 
the  surface  of  the  electrode.  This  acted  as  an  insulator 
or  retarded  the  passage  of  the  current.  When  on  the 
contrary  the  acid  was  too  strong  little  or  no  acetylene 
was  given  off.  Water  was  constantly  being  used  up 
to  cause  a  steady  evolution  of  acetylene,  and  accord- 
ingly it  was  difficult  to  keep  a  constant  concentration 
of  acid. 

The  apparatus  used  in  this  experiment  is  repre- 
sented in  figure  (  2  ) .  The  electrolyte  was  a  ten  per 
cent,  solution  of  ordinary  concentrated  sulphuric  acid. 
The  specific  gravity  of  the  acid  at  the  beginning  of 
the  operation  was  1.09  at  33°  C.  An  ordinary  thick- 
walled  gas-cylinder  was  used  as  an  electrolyzing 
vessel.  Contact  at  the  cathode  of  calcium  carbide 
was  made  by  means  of  a  mercury  connection.  A  bent 
glass  tube  within  which  was  a  copper  wire  served  to 
connect  the  mercury  at  the  bottom  of  the  vessel  with 
the  battery.  The  chloroform  was  gently  poured  upon 


—  49 


—  50  — 


the  mercury  to  the  height  of  several  centimeters,  and 
served  to  insulate  the  mercury  from  the  electrolyte. 
A  shapely  piece  of  calcium  carbide  was  then  floated 
upon  the  mercury  so  as  to  present  a  large  surface  to 
the  electrolyte.  The  acid  was  the  introduced  and  the 
electrolysis  was  begun,  using  a  platinum  anode.  The 
gasometer  was  filled  with  water  to  the  connection 
(  B ) .  The  siphon  (  D  )  was  also  completely  filled 
with  water.  A  funnel  connection  with  a  tube  bent 
at  right  angles,  was  placed  so  as  to  connect  all  the 
evolved  gases,  and  after  the  current  had  passed  for 
some  time  to  allow  the  air  to  be  driven  from  the  fun- 
nel, the  connection  was  made  at  (  B  )  and  the  gases 
drawn  into  the  gasometer  by  regulating  the  overflow 
of  water  from  the  siphon  at  (D).  Without  much 
careful  manipulation  the  gas  could  be  collected  as  fast 
as  it  was  given  off.  When  sufficient  gas  has  been 
collected  at  the  cathode  of  carbide  the  operation  was 
interrupted  and  the  products  analyzed. 

The  conditions  of  the  experiment  are  given  below. 


TEMPERATURE. 

CURRENT. 

TOTAL    GAS 
EXAMINED. 

ACETYLENE 
FOUND. 

ETHYLENE 
FOUND. 

RESIDUE. 

I.—  21°  C. 

2.25 

Amp. 

95.  ccm. 

25.8  ccm. 
28  per  ct. 

3.2  ccm. 
3  per  ct. 

64.  ccm. 
68.  5  per  ct 

SECOND   SERIES   OF  EXPERIMENTS  WITH  DILUTE  SULPHURIC 
ACID. 

A  solution  containing  equal  parts  of  strong  sul- 
phuric acid  of  the  specific  gravify  11.83,  an(^  °f 
water,  was  electrolyzed  in  an  apparatus  as  shown  in 
figure  (  3  ).  The  specific  gravity  of  the  diluted  acid 
used  as  an  electrolyte  was  1.479  at  4°°  C. 

A  calcium  carbide  cathode  was  used.     A  piece  of 


FIG. 3 


calcium  carbide  was  shaped  as  shown  in  the  illustra- 
tion, having  a  large  head  and  a  cylindrical  projection. 
Many  coils  of  fine  copper  wire  were  wound  around 
the  cylindrical  end,  thus  connecting  it  with  a  larger 
copper  wire  bent  like  a  fish-hook.  A  piece  of  thick 
rubber  tubing  served  to  insulate  the  copper  wires 
from  the  solution  so  that  the  electrical  connection 
with  the  electrolyte  was  obtained  only  at  the  globular 
end  of  the  calcium  carbide  electrode.  Mercury  was 
poured  into  the  rubber  tube  in  order  to  obtain  a  more 
perfect  connection.  A  platinum  anode  was  used. 
The  gas  was  collected  in  an  inverted  Mohr  burette 
into  which  the  electrolyte  was  drawn  to  the  stop- 
cock (E).  In  order  that  no  bubbles  of  gas  might  be 
lost,  a  funnel  was  held  under  the  burette  by  means 
of  a  bent  glass  rod  fastened  at  (  B )  with  a  rubber 
band. 

The  cathode  was  introduced  into  the  solution,  but 
no  gas  was  collected  until  the  current  had  become 
normal  as  shown  by  the  voltmeter  and  amperemeter. 
The  electrode  was  then  put  under  the  funnel  and  the 
duration  of  the  experiment  carefully  recorded  by 
means  of  a  stop-watch .  All  variations  in  the  current 
were  also  noted  by  the  voltmeter  and  amperemeter, 
and  recorded  as  they  occurred.  When  the  burette 
whose  capacity  was  about  fifty  to  sixty  cubic  centi- 
meters, was  filled,  the  operation  was  interrupted  and 
the  gas  transferred  to  a  Hempel  burette.  Its  volume 
was  then  recorded  and  the  gas  subjected  to  analysis. 
Acetylene  was  taken  out  with  ammoniacal  silver 
solution  in  the  Bunte-Seger  burette,  as  this  is  espe- 
cially adapted  for  shaking  the  gas  with  the  absorbent. 


—  53 


In  experiment  (  2  )  a  piece  of  muslin  was  tied  about 
the  electrode  in  order  to  retard  the  reaction  of  the 
dilute  acid  upon  the  calcium  carbide  and  thus  diminish 
the  amount  of  acetylene  given  out.  In  experi- 
ments (4)  and  (5)  a  stronger  acid,  consisting 
of  one  part  of  water  and  two  parts  of  concentrated 
acid  was  used.  Experiments  (  4  )  and  (  5 )  record 
the  results  obtained  at  an  anode  of  calcium  carbide. 
During  this  operation  great  deviations  in  the  strength 
of  current  were  noted.  Beginning  with  1.2  amp.  a 
sudden  fall  to  .9  amp.  occurred.  Then  came  respect- 
ively :  .8,  .7,  .9,  i.i  amp.,  and  again  a  sudden  rise 
was  noted  to  1.5,  1.6,  1.2,  and  1.4  amp. 

RESULTS  OF   THE  EXPERIMENTS. 


DURATION. 

TEMPERATURE. 

VOLTAGE. 

AMPERAGE. 

GAS  COLLECTED 

I.  —  90  Sec. 

38°  c. 

50. 

2-5-3 

25.4  ccm. 

II.—  20  Min. 

31°  c. 

20. 

.5  ainp. 

40.7  ccm. 

III.—  10       " 

32°  C. 

51- 

.6  amp. 

45.2  ccm. 

IV.—  20      " 

25°  C. 

2O. 

.2-.  3. 

18.4  ccin. 

V.-  4     " 

25°  C. 

TOO. 

i.6-.7. 

43  5  ccm. 

GAS  SOL.  IN 
WATER. 

C2H2. 

C2H4. 

H2. 

02. 

C02. 

CO. 

RESIDUA!, 
GAS. 

I.— 
II.— 

III.-9.7 
IV.— 
V.— 

54 
4-2 

2.7 
12.  1 

.2 
.2 
0. 

13-7 

1.8 
i-7 

i3-8 
2.4 

8.5 

6.  02  ccm. 

12.8  ccm. 
4.8  ccm. 

ELECTROLYSIS    OF    DILUTE    SULPHURIC    ACID    WITH    SLIGHT 
PRESSURE. 

The  electrolysis  of  sulphuric  acid  accompanied  with 
pressure  was  performed  in  a  Hoffman's  apparatus  as 
shown  in  figure  (  4  ).  Only  slight  pressure  was  here 
obtained ;  namely,  that  of  the  weight  of  the  column 


—  54  — 


-55- 

of  acid  about  two  feet  in  height.  Pencils  of  calcium 
carbide  were  used  as  electrodes.  They  were  fastened 
to  the  lower  limbs  of  the  apparatus  by  a  piece  of 
strong  soft  rubber  tubing,  and  well  secured  with 
copper  wires  in  order  to  prevent  leakage  of  acid.  The 
electrical  connections  were  made  by  mercury  contact. 
Two  small  beakers  were  filled  with  mercury,  and  the 
exposed  ends  of  the  calcium  carbide  electrodes  were 
immersed  in  the  metal  beyond  the  rubber  connection. 
All  action  of  air  or  of  moisture  was  prevented  on  the 
surface  of  the  carbide.  In  order  to  wash  away  the 
oxide  from  the  calcium  carbide  it  was  washed  with 
alcoholic  hydrochloric  acid,  and  the  alcohol  was  re- 
moved with  petroleum.  The  electrodes  were  wiped 
dry  with  a  cloth  before  the  operation.  The  petroleum 
oil  extracted  the  alcohol  from  the  electrode  and  the 
white  crystalline  structure  of  calcium  carbide  was 
brought  out.  When  commercial  calcium  carbide  was 
allowed  to  remain  for  some  days  under  petroleum, 
many  impurities  were  removed  and  the  clear  white 
crystals  of  the  compound  could  easily  be  observed. 
Moissan  first  showed  that  chemically  pure  calcium 
carbide  consisted  of  these  white  or  transparent 
crystals. 

When  the  electrodes  were  thus  treated  the  action 
of  dilute  sulphuric  acid  upon  them  was  diminished. 
No  impurities  were  introduced  into  the  subsequent 
products  of  electrolysis  as  the  oil  consisted  of  saturated 
hydrocarbons  not  acted  upon  during  the  operation. 
The  acid  used  in  the  electrolysis  consisted  of  a  mixture 
of  equal  parts  of  strong  commercial  sulphuric  acid 
(Sp.  Gr.  1.82),  and  distilled  water.  The  current 


-56 


was  allowed  to  pass  for  some  time  before  the  gas  was 
collected.  The  anode  and  cathode  gaseous  products 
were  separately  analyzed. 

RESULTS  OF  THE  EXPERIMENT. 


TEMPERATURE. 

VOLTAGE. 

AMPERAGE. 

GAS    COLLECTED. 

Anode. 
Cathode. 

18°  -  28°  C. 
i8°-28°  C. 

115. 
115. 

•5 

•5 

72.8 
42.4 

ACETYLENE. 

ETHYLENE. 

CARBON   DIOXIDE. 

Anode. 
Cathode. 

12.6 

18.2 

0. 

29.7 

ELECTROLYSIS  OE  CALCIUM  HYDROXIDE  SOLUTION  WITH 
CALCIUM  CARBIDE  ELECTRODES. 

As  calcium  carbide  was  very  quickly  and  violently 
acted  upon  by  water,  or  a  dilute  solution  of  calcium 
hydroxide,  some  device  had  to  be  used  to  moderate 
the  action.  The  electrode  was  soaked  for  some  time 
in  petroleum  oil,  or  when  this  was  not  used  the  elec- 
trode was  covered  with  a  piece  of  white  muslin. 
Precipitated  calcium  hydroxide  did  not  insulate  the 
current  as  effectively  as  calcium  sulphate.  The 
operation  was  performed  with  an  apparatus  as  shown 
in  figure  (3).  Experiment  (2)  gave  the  results 
obtained  at  an  anode  of  calcium  carbide. 

RESULTS  OF  THE  EXPERIMENTS. 


DURATION. 

TEMPERATURE. 

VOLTAGE. 

AMPERAGE. 

GAS  OBTAINED. 

I.—  80  Sec. 

15°  C. 

20. 

.6 

54.8  ccm. 

II.—  243  Sec. 

15°  C. 

53- 

1.2 

55.3  ccm. 

III.  -•  63  Sec. 

15°  C. 

53- 

i-5 

57.3  ccm. 

IV.—  124  Sec. 

85°  C. 

53- 

I.O 

46.6  ccm. 

V.—  105  Sec. 

93°  C. 

20. 

•  3 

39.4  ccm. 

—  57  — 


GAS  SOI,.    IN 
WATER. 

C2H2. 

C2H4. 

Bv 

02. 

C02. 

RESIDUAI, 
GAS. 

.8 
•9 
i-5 

466 
42.8 
42.5 
27.4 
31-5 

•4 

.6 

.8 

2.0 

3-8 

4-4 
4-5 
2-3 

4- 

4. 

4.    ccm. 
11.4  ccm. 
9.    ccm. 
13.    ccm. 
2.1  ccm. 

The  precipitate  of  the  electrolysis  of  calcium 
hydroxide  was  analyzed,  and  a  small  quantity  of  car- 
bonate was  found  to  be  present ;  thus  accounting  for 
lack  of  free  carbon  dioxide  in  the  gas  analysis  of  the 
anode  products.  Oxalic  acid  was  also  detected  as 
calcium  oxalate  by  the  qualitative  test.  It  was  like- 
wise determined  by  titration  with  a  solution  of 
standard  potassium  permanganate. 

ELECTROLYSIS  OP  CALCIUM   CHLORIDE  SOLUTION   WITH 
CALCIUM   CARBIDE  ELECTRODES. 

The  salts  of  calcium  may  be  regarded  as  the  typical 
electrolytes  for  calcium  carbide  electrode.  In  an  acid 
solution  the  calcium  of  the  carbide  becomes  a  part  of 
the  electrolyte  as  fast  as  it  dissolves,  and  thus  a 
mixture  of  electrolytes  is  avoided.  The  soluble  salts 
of  calcium  give  up  water  with  great  reluctance  and 
even  deliquesce  in  their  own  water  of  crystallization. 
It  is  easy  to  regulate  the  action  of  the  solution  of 
such  compounds  upon  the  easily  decomposed  calcium 
carbide.  In  order  to  obtain  good  results  in  the  elec- 
trolysis of  these  solutions,  concentrated  solutions  can 
not  be  used,  as  little  or  no  acetylene  is  given  off.  It 
is  necessary  to  add  water,  or  better  to  dilute  the  acid  in 
order  to  insure  a  sufficient  evolution  of  acetylene.  In 
solutions  of  calcium  chloride  and  calcium  nitrate  and 


-58- 

also  of  zinc  nitrate,  calcium  carbide  is  practically 
stable.  If  ethylene  is  formed  it  is  not  absorbed  by 
the  electrolyte.  Its  presence  can  be  decisively  deter- 
mined without  relying  on  the  iodoform  test  for  alco- 
hol when  ethylene  is  calculated  volumetrically.  If 
this  gas  can  not  be  found  in  the  products  of  electroly- 
sis, it  is  justifiable  to  ascribe  the  iodoform  precipitate 
to  aldehyde.  If  ethylene  is  not  found  it  is  most 
probable  that  free  alcohol  was  not  present  in  the 
products  of  electrolysis  of  solutions  of  sulphuric  acid. 
The  object  then  is  to  determine  whether  sufficient 
ethylene  is  formed  to  account  for  the  precipitate  of 
iodoform  obtained  from  the  electrolysis  of  solutions 
with  calcium  carbide  electrodes. 

In  the  experiments  to  be  described  the  solutions  of 
calcium  chloride  was  obtained  by  treating  pure  cal- 
cium carbonate  with  hydrochloric  acid.  After  filter- 
ing the  solution  it  was  evaporated  to  a  syrupy  consist- 
ency. It  was  not  necessary  to  remove  all  the  acid,  as 
this  was  afterwards  added  in  order  to  insure  a  good 
action  at  the  surface  of  the  electrode.  From  this 
syrupy  solution  an  electrolyte  could  be  obtained 
that  attacks  calcium  carbide  just  fast  enough 
to  insure  a  steady  stream  of  acetylene  while  the 
electrolysis  is  in  operation.  It  was  found  best  to  add 
hydrochloric  acid  rather  than  to  dilute  with  much  water 
as  strong  acid  solutions  attacked  calcium  carbide 
more  readily  than  weaker  aqueous  solutions.  The 
acid  served  to  keep  the  surface  of  the  carbide  elec- 
trode free  from  precipitate  of  hydroxide  or  basic 
insoluble  products  that  acted  as  an  insulator  to  the 
current.  A  solution  whose  concentration  corresponded 


-59- 

to  a  specific  gravity  of  1.235,  was  found  to  be  too 
strong,  for  only  forty  bubbles  of  gas  were  obtained  per 
minute.  It  was  further  diluted  until  its  specific 
gravity  of  1.2285  at  15.5°  C.  was  denoted,  and  this 
electrolyte  was  found  to  be  best  adapted  for  the 
process  of  electrolysis  at  ordinary  temperatures. 
When  the  operation  was  carried  at  a  temperature  of 
100°  C.  to  120°  C.  it  was  necessary  to  add  more  salt 
in  order  to  obtain  a  more  concentrated  solution. 

1 .  —  The  electrolysis  of  a  solution  of  calcium  carbide 
was  first  made  with  an  anode  of  calcium  carbide.     A 
current  of  one  ampere  to  one  and  one-fourth  amperes 
was  used,  and  an  electromotive  force  of  twenty  volts. 
A  quiet  evolution  of  gases  took  place  for  some  time, 
but   after   some   minutes  explosions  occurred  under 
the  liquid  at  the  carbide  anode.     It  was  not  consid- 
ered safe  to  collect  the  gas  in  quantity  owing  to  the 
explosive  nature  of  the  product.     A  continuous  vol- 
ley of  explosions  and  a  display  of  sparks  took  place 
at  the  electrode.     When  an  attempt  was  made  to  col- 
lect the  gas  in  a  test-tube  the  latter  was  shattered  by 
an  explosion.     Traces  of   tetrachloracetylene    were 
obtained  in  the  electrolysis  of  calcium  chloride  with  a 
calcium  carbide  anode. 

2.  —  With  the  same  current  the  cathode  reactions 
were  studied.     The  apparatus  used  is  shown  in  figure 
(  5  ).     The  cathode  consisted  of  a  large  piece  of  cal- 
cium carbide.      A  hole  was  bored  into  this  and  a 
large  copper  wire  fixed  into  it  with  fused  lead.     The 
anode  consisted  of  a  piece  of  platinum  foil  and  an 
ordinary   gas    cylinder  was    used    as    a  vessel    for 
electrolysis.     To  collect  the  gas  a  gasometer  was  at- 


—  6o 


tached  as  shown  in  figure  (  2  ).  The  entrance  of  the 
gas  was  controlled  by  allowing  water  to  flow  from  a 
siphon  which  was  regulated  with  a  stop- cock  (D). 
The  gas  was  collected  at  the  electrode  by  means  of  a 
wide-necked  bottle,  whose  bottom  had  been  removed. 
The  copper  wire  ( as  shown  in  figure  5  )  that  served 
as  a  connection  with  the  electrode  was  passed  through 
the  cork  of  a  Wiirtz  tube  and  the  gas  carried  off  by 
the  side  tube.  The  Wiirtz  tube  itself  was  fitted  to 
the  bottle  by  a  large  rubber  stopper.  After  contin- 
uing the  electrolysis  for  some  time  the  gas  was  col- 
lected and  afterwards  analyzed.  When  the  experi- 
ment was  carried  on  too  long  the  calcium  chloride  be- 
came saturated  with  acetylene,  and  explosions  took 
place  at  the  platinum  anode.  Of  101  ccm.  of  gas 
collected,  88  ccrn.  were  acetylene  and  1.6  ccm.  were 
absorbed  over  fuming  sulphuric  acid,  corresponding 
to  ethylene. 

3.  —  The  electrolysis  of  a  solution  of  calcium 
chloride  at  a  temperature  of  100°  C.  was  tried  in  or- 
der to  ascertain  if  different  results  were  obtained  from 
those  resulting  at  ordinary  temperatures.  The  appar- 
atus used  was  shown  in  figure  (3).  Test  experiments 
were  first  made  to  find  if  explosions  took  place  at  the 
anode  in  the  heated  solution.  After  some  time  it 
was  concluded  that  the  operation  could  be  carried  on 
with  safety. 

The  temperature  of  the  solution  in  this  experiment 
was  110°  C.  No  explosion  occurred  with  a  current 
strength  of  .5  amperes  and  a  potential  of  10  volts. 
Again  at  a  temperature  of  1 16°  C.  and  with  a  current 
of  1.2  to  1.3  amperes  and  20  volts,  no  explosions  were 


—  62  — 

observed.  It  was  then  thought  safe  to  collect  some 
of  the  gaseous  products.  In  the  next  attempt  a  cur- 
rent strength  of  .5  amp.  and  10  volts  were  used  and 
42.8  ccm.  were  collected  in  three  minutes  and  five 
seconds.  No  explosions  occurred  during  the  experi- 
ment. On  examining  the  gas,  40.2  ccm.  were  found 
to  be  acetylene,  thus  showing  that  no  free  chlorine 
gas  had  been  obtained.  Another  operation  was  per- 
formed with  a  current  strength  of  i  to  1. 1  amp.  and 
20  volts  at  a  temperature  of  112.  To  prevent  accu- 
mulation of  gas  bubbles  on  the  carbide  anode,  a  piece 
of  cloth  was  tied  about  it.  The  gas  collected  took 
fire  spontaneously  in  the  burette  with  the  separation 
of  carbon.  About  31  ccm.  of  the  residual  gas  were 
passed  into  the  Hempel  burette.  All  but  18.8  ccm. 
were  absorbed  by  the  water,  showing  it  to  be  hydro- 
chloric acid  gas  formed  during  the  explosion.  Of  the 
residue  13.8  ccm.  were  acetylene  and  neither  oxygen 
or  carbon  dioxide  could  be  detected. 

4.  —  In  the  fourth  experiment  a  calcium  carbide 
anode  and  a  platinum  cathode  were  used.  With  a 
current  strength  of  20  volts  and  i.i  amp.,  explosions 
again  resulted  at  the  anode  at  ordinary  temperatures. 
A  black  deposit  was  left  on  the  platinum  cathode 
This  was  insoluble  in  dilute  or  strong  hydrochloric 
acid  and  somewhat  soluble  in  very  strong  nitric  acid. 
Heated  on  platinum  no  residue  was  left.  It  was  con- 
cluded that  the  deposit  consisted  of  carbon  electroly- 
tically  separated.  Similar  deposits  of  carbon  at  the 
cathode  have  been  obtained  by  various  investigators. 


63- 


ELECTROLYSIS  OF  ZINC  CHLORIDE  SOLUTION  WITH  CALCIUM 
CARBIDE  ELECTRODES. 

Zinc  chloride  was  electrolyzed  under  similar  con- 
ditions as  already  described  in  the  electrolysis  of 
calcium  chloride.  The  salt  was  prepared  from 
arsenic- free  zinc  with  dilute  hydrochloric  acid.  The 
apparatus  was  of  the  type  shown  in  figure  (4). 
After  the  solution  had  been  evaporated  to  concentra- 
tion, it  was  used  as  an  electrolyte  both  at  ordinary 
temperatures  and  above  100°  C.  The  solution  was  in 
one  of  these  operations  boiled  while  the  current  was 
passed  through  it.  In  the  first  experiment  the  anode 
was  a  piece  of  calcium  carbide  and  a  zinc  rod  was 
used  as  a  cathode.  An  electromotive  force  of  20  volts 
was  applied,  and  this  gave  a  varying  current  of 
strength  ranging  as  follows;  (.1  amp.,  .6,  6.5,  4.5, 
5,  5-5-6,  6.5,  6.6,  6.8,  7.5,  7.3,  7.6,  and  finally  8  am- 
peres ) 

After  the  operation  the  calcium  carbide  was  covered 
with  grains  of  carbon.  No  explosion  was  noticed.  A 
deposit  of  crystalline  zinc  took  place  on  the  cathode 
of  platinum. 

When  calcium  carbide  was  used  as  a  cathode  in  an 
electrolyte  of  zinc  chloride,  no  ethylene  was  obtained. 
In  the  third  experiment  performed  with  a  calcium 
carbide  cathode,  and  a  zinc  anode,  the  carbide  became 
covered  with  large  crystals  of  zinc  The  solution  of 
zinc  chloride  was  acidified  before  the  electrolysis,  but 
most  of  the  acid  was  driven  off  by  the  heat  of  the 
operation. 

In  the  first  experiment  no  gas  was  collected.  The 
object  of  the  operation  was  to  find  whether  chlorine 


-64- 


exploded  with  nascent  acetylene  at  the  anode.  It  was 
found  that  the  chlorine  united  with  the  calcium  of 
the  carbide,  while  the  carbon  was  separated  in  a  hard 
gritty  mass.  L,ittle  or  no  free  chlorine  was  noticed. 
The  temperature  of  this  operation  ranged  from 
124°  C.  to  132°  C.  No  reason  has  been  found  for  the 
great  variations  of  current  that  were  observed. 

RESULTS  OF  THE  EXPERIMENTS. 


TIME. 

TEMP. 

VOLTS 

AMP. 

GAS 

OBT'D. 

C2H2. 

45-2 
7-3 

C2H4. 

H2. 

[I.-3^  min. 

io6°C 
ioo°C. 

20. 

10. 

5-5 
5 

53    ccm 
53.8  ccm 

o. 

0.2 

23-3 

ELECTROLYSIS    OF   CALCIUM    NITRATE    SOLUTION   WITH    CAL- 
CIUM CARBIDE  ELECTRODES. 

Calcium  nitrate  like  calcium  chloride  is  well  adapted 
for  electrolytic  work  with  calcium  carbide  electrodes. 
In  acidified  solution  the  product  of  reaction  of  the 
acid  electrolyte  upon  the  electrode  is  calcium  nitrate, 
and  thus  mixtures  of  electrolytes  are  avoided.  Cal 
cium  nitrate  is  as  deliquescent  as  the  chloride,  and 
solutions  of  any  concentration  may  be  obtained. 

In  the  first  experiment  the  electrolysis  was  per- 
formed at  ordinary  temperatures  and  under  atmos- 
pheric pressure,  in  the  other  operations  additional 
pressure  was  applied.  The  apparatus  in  the  first 
operation  was  of  the  type  as  shown  in  figure  (  3  ) ,  and 
a  cathode  of  calcium  carbide  was  used.  As  a  con- 
centrated solution  of  calcium  nitrate  does  not  attack 
the  carbide  electrode  very  readily  even  in  the  presence 
of  nitric  acid,  water  was  added  until  a  good  evolution 


-65- 


of  acetylene  was  obtained.     The  temperature  in  the 
first  experiment  rose  from  18°  C.  to  30°  C. 

RESULTS  OF  THE  EXPERIMENT. 


TEMP. 

VOLTS 

AMPERES. 

GAS 

OBT'D. 

C2H2. 

ABSORPTION 
BY  H2S2O7. 

1  8°  -30°  C. 

10. 

2.7-35. 

53.4  ccm 

14.4 

0.8  ccm. 

ELECTROLYSIS  OF  CALCIUM  NITRATE  UNDER  PRESSURE. 

An  attempt  was  next  made  to  electrolyze  calcium 
nitrate  solution  with  calcium  carbide  electrodes  under 
pressure.  In  view  of  the  difficulties  of  obtaining 
proper  connections  with  the  carbide  electrode,  it  was 
not  easy  to  find  a  completely  desirable  method  with 
apparatus  that  could  easily  be  set  from  the  ordinary 
laboratory  supplies.  The  apparatus  used  is  shown  in 
figure  (  6  ). 

The  vessel  in  which  the  electrolysis  was  performed 
was  a  thick-walled  flask  having  two  ground  glass 
openings,  and  a  capacity  of  500  cubic  centimeters.  Into 
the  larger  of  these  openings  a  calcium  carbide  elec- 
trode (  A  )  was  fitted.  The  smaller  opening  (  B  )  was 
closed  with  a  two-holed  rubber  stopper  that  was 
fastened  to  the  apparatus  with  shellac.  Through  one 
of  the  holes  of  this  stopper  passed  the  tube  (C),  to 
conduct  the  gas  into  the  Hempel  burette  (D),  the 
amount  of  gas  being  regulated  by  the  stop-cock  (  K). 
Through  the  other  hole  passed  the  long  glass  tube 
(  F  )  which  went  to  the  bottom  of  the  vessel  and  dip- 
ped below  the  surface  of  a  layer  of  zinc  amalgam, 
(G).  This  tube  was  nearly  two  meters  long  and 
was  graduated  in  centimeters  throughout.  Within 


66 


-67- 

this  passed  a  small  copper  wire  making  connection 
with  the  zinc  amalgam  that  served  as  an  anode.  The 
tube  served  also  as  a  pressure  gauge,  the  amount  of 
pressure  being  approximately  indicated  by  the  height 
of  the  mercury  in  the  tube,  as  the  gas  increased 
within  the  apparatus.  The  amount  of  pressure  was 
read  off  on  the  tube  in  centimeters.  The  function  of 
the  amalgam  was  to  reduce  the  oxygen  ions  given  off 
at  its  surface  with  the  formation  of  water.  The  acid 
present  in  the  electrolyte  acted  on  the  amalgam  giv- 
ing off  hydrogen  which  united  with  the  oxygen  set 
free  to  form  water. 

The  gas  was  allowed  to  escape  only  at  definite 
stages  and  only  as  fast  as  it  was  formed  within  the 
apparatus.  This  was  done  by  regulating  the  outflow 
at  ( G )  through  the  capillary  tube  and  into  the 
Hempel  burette.  Pure  mercury  was  poured  into  the 
long  tube  to  displace  the  amalgam  therein  and  thus 
give  a  correct  reading  of  the  pressure. 

The  calcium  carbide  cathode  is  shown  more  in 
detail  in  figure  (  7  )  in  order  to  illustrate  the  connec- 
tion of  the  various  parts  with  more  exactness. 
The  calcium  carbide  (  A  )  was  made  into  a  pencil  of 
as  evenly  cylindrical  a  shape  as  possible.  This  was 
fitted  into  a  small  screw-cap  specimen-bottle  after  its 
bottom  has  been  removed.  A  piece  of  soft  rubber 
tubing  (  B  )  passed  closely  and  tighty  with  the  car- 
bide into  the  bottle  and  was  reversed  outside  of  the 
same.  The  rubber  was  well  tied  to  both  carbide  and 
bottle,  so  that  any  pressure  within  the  apparatus 
rendered  the  connections  closer,  and  less  liable  to 
leak,  and  at  the  same  time  held  the  electrode  in  posi- 


—  68  — 

tion.  Around  the  bottle  was  fitted  a  good  cork  (  D  ) 
which  was  fixed  to  the  opening  with  asphalt,  and 
allowed  to  dry  several  days  in  an  atmosphere  free 
from  moisture.  The  space  (  C )  in  the  small  bottle, 
not  occupied  by  the  electrode  was  filled  with  mercury 
to  secure  good  electrical  contact.  When  good  con- 
tact was  not  obtained  the  heat  became  so  great  at  the 
surface  of  the  calcium  carbide  as  to  ignite  the  rubber, 
owing  to  the  resistance  of  the  cathode  to  the  passage 
of  current.  A  rubber  washer  (  K  )  with  a  hole  in  its 
center  was  inserted  above  the  mercury.  The  plate 
(  F )  of  chemically  pure  iron  was  put  in  to  prevent 
the  mercury  from  attacking  the  metal  cap,  which  was 
screwed  on  tightly  over  the  glass  bottle. 

The  circuit  was  closed  after  connecting  (  H )  in 
(  Figure  6  )  with  the  battery  by  contact  of  the  wire 
(  I )  with  the  screw-cap  of  the  bottle.  The  current 
passed  through  the  iron  plate  and  mercury  to  the 
electrode  ( A ) ,  where  the  gaseous  products  were 
evolved. 

When  the  apparatus  was  ready  and  the  stoppers 
were  well  dried,  the  mercury  amalgam  was  poured 
into  the  vessel  by  a  long  thistle-tube  drawn  out  at 
the  end.  The  acidified  nitrate  solution  was  poured 
in  through  the  short  glass  tube,  ( C )  by  inserting 
within  ( C  )  a  thistle-tube  drawn  out  to  a  fine  point. 
The  vessel  was  filled  about  five-sixths  full  of  the 
liquid.  The  apparatus  was  connected  with  a  Hempel 
burette  and  electrolysis  begun  by  making  contact  at 
(H)  and  (I).  Two  experiments  were  made  and 
results  obtained  at  three  different  stages  of  pressure 
for  each  operation. 


-69- 

In  the  first  experiment,  the  operation  was  carried 
on  with  a  current  of  one-half  an  ampere  and  ninety- 
nine  volts  electromotive  force.  When  the  contact 
was  made  the  gas  was  allowed  to  pass  out  for  some 
time.  Then  the  stop-cock  at  (  K )  was  closed,  and 
the  mercury  rose  slowly  in  the  tube  (  F ) ,  as  the 
pressure  within  increased.  When  a  pressure  of 
1530  mm.  of  mercury  was  obtained,  the  gas  at  (  K) 
was  allowed  to  pass  into  the  Hempel  burette  only  so 
fast,  however,  as  to  keep  the  reading  continually  at 
1530  mm.  while  the  burette  was  being  filled.  The 
stop-cock  at  (K)  was  closed  and  another  Hempel 
burette  substituted  to  obtain  products  at  higher  pres- 
sure. The  experiment  was  continued  with  the  inten- 
tion of  obtaining  the  gas  at  a  pressure  of  1900  mm. 
When  the  column  of  mercury  reached  1860  mm.  of 
mercury  in  height,  the  calcium  carbide  electrode  was 
violently  blown  out  with  a  loud  report. 

Another  attempt  was  made  after  the  apparatus  had 
been  set  up  again.  The  gas  was  collected  at  different 
stages  of  the  experiment : 

i. —  At  ordinary  atmospheric  pressure. 

2. —  At  a  pressure  of  1 140  mm.  of  mercury. 

3. —  At  a  pressure  of  1460  mm.  of  mercury. 

At  a  pressure  of  1610  mm.  the  cathode  was  again 
forced  out  and  thus  only  three  specimens  of  gas  were 
obtained.  Owing  to  the  fact  that  so  little  was  left 
after  the  elimination  of  acetylene  the  residues  of  the 
three  analyses  were  united  and  examined  for  ethy- 
lene,  hydrogen  and  ethane.  The  ethane  was  deter- 
mined with  the  Winckler's  pipette  and  as  no  diminu- 
tion of  volume  occurred,  it  was  then  passed  into  the 


—  70  — 


explosion  pipette  over  mercury  and  exploded  with  a 
spark  from  an  induction  coil.  When  the  gas  then 
passed  over  caustic  potash  only  5.4  ccm.  of  gas  were 
absorbed.  Accordingly  only  traces  of  saturated  hydro- 
carbons were  present. 

RESULTS  OF  THE  EXPERIMENTS. 


TEMP. 

PR'SSURE 

VOI/T. 

AMP. 

GAS  COL- 
LECTED. 

ACETYL'NE 

I.  —  16°  C. 
II.  —  16°  C. 
III.  —  16°  C. 
IV.  —  16°  C. 

1530  mm. 
760  mm. 
1140  mm. 
1460  mm. 

99- 

IOO. 
IOO. 
IOO 

0.5 
•I—  -3 
i  —  -3 
•  i—  -3 

58.7 
82.6 

79- 

82. 

32.4 

78.61 
76.3  \-   toll 
79-    J 

ETHYLENE. 

HYDROGEN. 

ETHANE- 

RESIDUE  OF 
GAS. 

I.  — 
II.— 

o 
2.  ccm. 

.5  ccm. 

2.7  ccm. 

4-5  ccm. 

ELECTROLYSIS  OF    NITRATES     AT     A    TEMPERATURE    ABOVE 
100°  C. 

ELECTROLYSIS   OF   CALCIUM  NITRATE. 

After  electrolyzing  calcium  nitrate  at  ordinary  tem- 
peratures, with  or  without  pressure,  and  not  obtaining 
any  marked  results  as  to  yield  of  ethylene  at  a  cathode 
of  calcium  carbide,  the  next  attempt  was  made  to 
electrolyze  the  same  solution  at  a  higher  temperature. 
This  experiment  was  tried  with  as  concentrated  a 
solution  as  yielded  a  good  quantity  of  acetylene  in 
the  heated  electrolyte  in  the  presence  of  nitric  acid. 
Nitric  acid  had  been  added  before  boiling  but  most  of 
it  was  driven  off  at  the  boiling  point  of  the  solution. 
Before  collecting  the  gaseous  products  the  current 


was  allowed  to  pass  for  some  time  in  order  to  obtain 
a  uniform  action  and  a  steady  flow  of  gas. 

In  the  first  experiment  a  cathode  of  calcium  carbide 
was  used  and  a  piece  of  platinum  foil  as  an  anode. 
The  apparatus  was  of  the  type  shown  figure  (  3  ) . 
Brown  fumes  of  the  oxides  of  nitrogen  were  given 
off.  After  the  electrolysis  these  oxides  were  reab- 
sorbed  by  the  electrolyte  and  the  operation  had  to  be 
repeated  in  order  to  obtain  sufficient  gas  to  submit  to 
analysis.  Another  constituent  of  the  gaseous  pro- 
duct was  absorbed  in  the  water  of  the  Hempel 
burettes  after  standing  for  some  hours.  In  the  first 
experiment  the  gas  was  passed  over  caustic  potash  in 
order  to  remove  the  acid  vapors  of  the  oxides  of 
nitrogen. 

The  first  and  second  experiments  record  the  cathode 
reactions,  whereas  the  third  gives  the  anode  products. 

RESULTS  OP  THE  EXPERIMENTS. 


TEMPERATURE. 

voi/rs 

AMP. 

GAS   COI,- 
I,ECTED. 

GAS  SOIvUBIvE 
IN  WATER. 

I.—  106.5°  C. 
II.—  107.5°  C. 
-104  5°  C. 
III.—  110°  C. 

10. 

10. 
10 

5-4 

6-5-3 
6-4.6 

40.4  ccm. 

58.5  ccm. 
36  8  ccm. 

I. 

12-5 

3- 

T    

II.'  — 
III.— 

OXY- 
GEN. 

ABSORPTION 
BY  KOH. 

C2H2. 

ABSORPTION  BY 

H2SO4*SO3. 

HYDRO- 
GEN. 

RESI- 
DUE. 

•4 

10. 

8.6 

20. 
14-3 

9- 
15-7 
10.5 

24. 

9- 

ELECTROLYSIS  OF  ZINC   NITRATE. 


Calcium  carbide  was  used  as  a  cathode  in  the  elec- 
trolysis of  a  concentrated  acidified  solution  of  zinc 


nitrate.  The  apparatus  represented  in  figure  (  3 ) 
was  used.  In  all  the  experiments  performed  with 
this  electrolyte  great  variations  of  current  took  place. 
Brown  fumes  were  evolved  both  at  the  anode  and 
at  the  cathode  of  calcium  carbide  when  a  solution 
was  electrolyzed.  The  operation  had  to  be  inter- 
rupted several  times  to  allow  the  acid  fumes  to  be 
reabsorbed  by  the  solution.  In  this  way  sufficient 
gas  was  collected  to  be  submitted  to  analysis. 

In  the  second  and  third  experiment  of  this  series 
the  anode  actions  were  studied.  The  gas  that  was 
collected  was  allowed  to  remain  in  the  burettes  sev- 
eral days  in  order  to  take  up  acid  vapors  given  off 
during  the  electrolysis. 

RESUI/TS  OF  THE  EXPERIMENTS. 


DURATION. 

TEMPERATURE 

voi/r. 

AMP. 

GAS  COUvECTED. 

I.— 
II  — 
III.— 

2^M. 

25Sec. 

ii2.5°-io6°  C. 
109°    -100°  C. 
io9.5°-n6.5°  C. 

10. 

10. 

10. 

3-5-5- 

7-5-8. 
3-5-5 

41. 
51.8 
29.8- 

GAS  SOLUBLE 
IN  WATER. 

ACETYLENE. 

GAS    ABSORBED   BY 

H2S04-H«)SOR. 

RESIDUE. 

I.- 
II.— 
III.— 

4-3 
17.9 

20.6 

39-3 
2.4 

14.8 
44 

83 

As  in  the  experiments  just  described  in  the  elec- 
trolysis of  nitrates  at  higher  temperatures  a  consider- 
able absorption  took  place  when  the  gas  freed  from 
acetylene  was  passed  over  fuming  sulphuric  acid,  it 
was  necessary  to  ascertain  whether  it  were  ethylene. 
Since,  however,  the  same  absorption  occurred  when 
the  anode  products  were  thus  treated  it  was  evident 


—  73- 

that  the  gas  could  not  be  ethylene.  In  order  to  show 
that  no  ethylene  was  present  as  a  product  of  the 
cathode  reactions  when  a  heated  solution  of  nitrates 
was  electrolyzed,  the  experiments  were  repeated  and 
after  all  the  acetylene  had  been  removed,  the  residual 
gas  was  passed  over  bromine  water  in  a  Hempel 
pipette  and  likewise  into  the  Bunte-Seger  burette 
where  the  gas  was  shaken  with  bromine  water.  Abso- 
lutely no  absorption  was  obtained  thus  clearly  show- 
ing that  the  gas  was  not  ethylene  nor  any  other 
unsaturated  hydrocarbon. 

The  gas  could  not  have  been  nitrogen  trioxide  or 
peroxide  as  these  are  absorbed  by  water  or  at  least 
by  caustic  potash.  In  order  to  show  that  the  gas 
absorbed  by  the  sulphuric  acid  in  the  pipette  was 
nitric  oxide,  the  gas  was  collected  in  considerable 
quantity.  The  solution  of  calcium  nitrate  was  elec- 
trolyzed in  a  flask  fitted  with  a  three-holed  stopper. 
The  platinum  anode  was  contained  in  a  Gooch  tube 
dipping  below  the  electrolyte  so  that  no  gas  from  the 
anode  could  escape  into  the  flask  but  was  carried  away 
as  fast  as  it  was  formed.  A  pencil  of  calcium  carbide 
served  as  a  cathode,  and  the  gas  evolved  was  carried 
through  a  tube  bent  at  right  angles  into  a  gasometer. 
The  gas  was  allowed  to  remain  in  the  gasometer  for 
several  weeks  to  remove  all  the  other  oxides  of  nitro- 
gen. When  air  was  then  drawn  into  the  flask  the 
presence  of  nitric  oxide  was  manifested  by  the  forma- 
tion of  brown  fumes  of  peroxide.  The  absorption 
over  fuming  sulphuric  acid  was  then  concluded  to  be 
due  to  nitric  oxide  according  to  the  reaction  : 


—  74  — 


ONO 


3S03-f  2NO  = 


O      +S02. 
- 

ONO 


ELECTROLYSIS  OF   MERCURIC   NITRATE. 

In  electrolyzing  a  solution  of  the  salt  a  cathode  of 
calcium  carbide  was  used  in  an  apparatus  as  shown 
in  figure  (3).  As  mercuric  nitrate  is  very  little 
soluble  in  water,  a  solution  was  heated  with  an  excess 
of  the  solid  remaining  in  the  vessel  during  electrolysis 
so  that  the  quantity  of  the  solution  might  remain 
constant.  An  anode  of  platinum  was  used  and  nitric 
acid  was  added  to  the  solution.  Most  of  the  acetylene 
given  off  from  the  electrode  united  with  the  mercuric 
nitrate  to  form  compounds  described  by  Hoffman.1 
The  mercuric  nitrate  did  not  dissolve  fast  enough  to 
permit  a  slow  action  at  the  cathode. 

RESULTS  OF  THE  EXPERIMENT. 


TEMPERATURE- 

VOLT. 

AMP. 

GAS  COLLECTED 

^2^2- 

C2H4. 

87°-97°C. 

50. 

.9-1.2. 

•J9.2 

8.2 

.6 

An  attempt  was  made  to  repeat  this  experiment, 
but  the  solution  had  become  so  dilute  and  the  action 
on  the  electrode  so  rapid  that  of47.4ccm.  of  gas,  32.2 
ccm.  were  found  to  be  acetylene. 

In  the  examination  of  ammonium  nitrate  in  a 
heated  solution,  with  a  cathode  of  calcium  carbide,  a 
large  proportion  of  acetylene  was  obtained,  ammonia 


1  Ber.  31,  2213. 


-75- 

gas  was  evolved,  but  practically  110  other  gaseous 
products  resulted.  Sodium  hyposulphite,  stannic 
chloride  and  various  other  salts  were  also  electrolyzed 
with  calcium  carbide  electrodes,  but  no  results  were 
obtained  that  differed  from  those  already  recorded. 
In  the  electrolysis  of  cupric  ammonium  chloride  no 
gaseous  products  could  be  collected  owing  to  the 
voluminous  precipitates  that  clogged  up  the  burette. 
The  precipitate  was  first  of  a  light  green  color,  a 
brown  powdery  precipitate  was  then  formed  and 
finally  it  became  black.  These  compounds  were,  how- 
ever, formed  independently  of  the  action  of  current, 
as  was  subsequently  found  on  heating  the  double 
chloride  with  calcium  carbide. 

From  the  results  of  the  investigation  just  described 
it  is  evident  that  if  acetylene  unites  with  nascent 
hydrogen  at  the  cathode  only  the  faintest  traces  of 
ethylene  were  found.  In  no  experiment  performed 
were  more  than  traces  of  ethyleue  at  a  cathode  of  cal- 
cium carbide  obtained.  The  formation  of  alcohol  at 
the  cathode,  mentioned  by  Bilitzer,  does  not  seem  to 
me  to  have  been  sufficiently  substantiated.1  It  has 
been  shown  that  acetylene  in  the  presence  of  sulphuric 
acid  gave  acetaldehyde.  This  gave  the  iodoform 
test  as  readily  as  alcohol.  Since  with  unplatinized 
electrodes  no  ethyleue  is  obtained  at  the  cathode,  it 
may  be  concluded  that  the  synthesis  of  the  gas 
results  from  catalytic  action  of  the  reduced  platinum 
in  effecting  the  union  of  acetylene  and  hydrogen. 
This  synthesis  was  in  fact  effected  by  Wilde1  as 

1  Ber.  7,353.  (Bull,  d'  Acad.  Royal,  de  Belg.  2,  XXI.,  No.  I, 
1874.) 


-76- 

already  referred  to  in  the  introduction  to  this  work. 
Sufficient  ethylene  was  not  formed  in  Bilitzer's  ex- 
periment to  account  for  the  amount  of  iodoform  pre- 
cipitate actually  obtained  from  the  products  of 
electrolysis  of  sulphuric  acid.  As  practically  no  ethy- 
lene was  obtained  the  resulting  iodoform  is  to  be 
referred  to  the  formation  of  acetaldehyde. 

In  fact,  by  passing  acetylene  for  some  time  into 
reduced  platinum  suspended  in  water  acidified  with 
dilute  nitric  acid,  aldehyde  was  formed.  When  the 
filtered  solution  was  treated  with  iodine  and  caustic 
potash,  an  abundant  precipitate  of  iodoform  was 
obtained. 


—  77  — 


THE  CHLORINATION  OF  ACETYLENE. 


HISTORY    OF    THE    REACTION    OF     CHLORINE     WITH 
ACETYLENE. 

The  action  of  acetylene  upon  chlorine  was  first  ob- 
served in  1835  by  Edmond  Davy,1  who,  in  a  paper 
read  before  the  Royal  Dublin  Society,  reported  the 
instantaneous  explosion  that  occurred  when  the  two 
gases  were  brought  together.  No  further  investiga- 
tion of  this  subject  seems  to  have  been  made  until 
1860  when  Berthelot2  who  had  given  the  hydrocarbon 
its  name,  acetylene,  declared  that  the  gas  mixed  with 
chlorine  gave  rise  to  violent  explosions  in  diffused 
daylight.  He  thus  seems  to  infer  that  the  sudden 
decomposition  noticed  by  Davy  is  primarily  due  to 
the  influence  of  actinic  light  rays.  Wohler3  two  years 
later  refers  to  the  explosiveness  of  mixtures  of 
chlorine  and  acetylene,  but  assigns  no  cause  for  the 
phenomenon. 

The  same  year  Berthelot  stated  the  failure  to  make 
di-chloride  of  acetylene,  (C2H2Cl2),by  direct  union 
of  the  constituents,  owing  to  the  violent  explosions 
that  resulted. 

In  1866,  however,  Berthelot4  came  to  the  conclusion 

1  Ann.  23,  144. 

2  C.  R.,  sr,  1044. — Ives  Carbures  D'Hydrogene  Paris,   1901. 
'Ann.  124,  220. 

4  Les  Carbures  D'Hydrogene  t.  I,  p.  309. 


-78- 

that  a  mixture  of  acetylene  and  chlorine  could  be 
preserved  in  the  dark  for  several  days,  but  that  an 
explosion  took  place  as  soon  as  brought  to  the  light. 
He  found,  moreover,  that  under  certain  conditions, 
the  exact  nature  of  which  he  confessed  himself  unable 
to  determine,  the  di-chloride  of  acetylene  was  formed. 

The  union  would  continue  quietly  for  some  time, 
yet  finally,  and  almost  invariably  a  violent  detona- 
tion, or  spontaneous  noiseless  combustion  with  the 
evolution  of  light  and  deposition  of  much  carbon  re- 
sulted. These  effects  were  noticed  as  well  when  an 
excess  of  chlorine  or  an  excess  of  acetylene  was  used, 
or  even  when  either  gas  was  diluted  several  times  its 
volume  of  hydrogen  or  carbon  dioxide.  He  now 
refers  the  cause  of  the  phenomenon  to  the  formation 
and  spontaneous  decomposition  of  the  substituted 
chloride  of  acetylene,  (C2HC1),  which  breaks  down 
spontaneously  and  violently  in  contact  with  oxygen 
of  the  air.  He  confesses,  however,  his  inability  to 
assign  a  definite  cause  supported  by  the  evidence  of 
experiment.  He  believes  the  explosion  results  be- 
cause of  a  ' '  certain  molecular  inertia ' '  at  the  moment 
the  gases  are  mixed,  or  on  calorific  phenomena  at  the 
point  where  the  reaction  begins. 

In  1880  some  light  .seemed  to  be  thrown  upon  the 
subject  by  Wallach.1  He  found  that  when  heating 
dichlor- acrylic  acid,  or  its  salts  with  alkalies  or  the 
hydrates  of  the  alkaline  earth  metals,  a  gas  was  given 
off  which  took  fire  spontaneously,  or  exploded  in  con- 
tact with  the  air.  By  diluting  the  evolved  gas  with 

1  Ann.  203,  83. 


—  79  - 

hydrogen  aud  passing  it  into  bromine,  he  obtained 
and  analyzed  the  compound,  C2HC1  Br4  thus  show- 
ing the  composition  of  the  gas  to  be  a  substituted 
chlor-acetylene  of  the  formula  C2HC1.  As  already 
stated,  Berthelot  referred  to  this  substance  as  the 
cause  of  the  explosion  when  acetylene  and  chlorine 
are  directly  united. 

In  1884  Schlegel1  came  to  the  conclusion  that  the 
sole  cause  for  the  phenomenon  of  spontaneous  decom- 
position of  a  mixture  of  the  two  gases  is  the  action  of 
light  rays.  He  showed  that  the  mixture  could  be 
kept  for  an  indefinite  time  in  the  dark,  but  that  the 
light  of  a  gas  flame  is  sufficient  to  explode  the  gases. 

Romer2  two  years  later  assigns  another  cause  for 
the  phenomenon  of  detonation.  He  allowed  the 
acetylene  he  used  to  stand  some  time  in  diffuse  day- 
light, and  found  that  the  walls  of  the  glass  vessel 
containing  the  gas  became  coated  with  a  brown  pro- 
duct. This  he  supposed  to  be  a  polymerized  poly- 
acetylene  resulting  from  the  di-acetylene  (  C4H2 ) , 
discovered  shortly  after  by  Bayer.3  Romer  referred 
the  explosion  of  acetylene  and  chlorine  to  the  im- 
purity just  mentioned  because  of  its  instability. 
Acetylene  purified  by  exposure  to  light  before  being 
brought  into  contact  with  chlorine,  united  quietly  to 
form  addition  products,  whereas  freshly  prepared 
acetylene  always  gave  rise  to  a  sudden  explosion. 
Romer  concludes  that  acetylene  like  ethane,  ethy- 

1  Ann.  226,  153. 

2  Ann.    233,    215    and    184,  (3)  Ann.  Chim.  Phys.  16,473.— 
Carb.  d'Hyd.  vol.  I. 

3  Ber.  18,  2272. 


—  8o  — 

lene,  and  carbon  monoxide  are  analogous  in  their 
action  towards  chlorine,  and  like  hydrogen,  will 
explode  with  chlorine  only  under  the  influence  of  the 
action  of  rays  of  light. 

In  1872  Berthelot  and  Jungfleisch  effected  the 
chlorination  of  acetylene  by  means  of  antimony 
pentachloride.  This  compound  absorbs  the  gas  with 
the  formation  of  a  substance  corresponding  to  the 
formula  C2H2SbCl5,  which  separates  in  well  denned 
crystals.  With  water,  decomposition  takes  place  and 
on  heating,  a  mixture  of  di-and  tetra-chlorides  of 
acetylene  distills  over.  When  the  crystalline  com- 
pound is  heated  with  an  excess  of  antimony  penta- 
chloride, pure  tetrachlorethane  is  obtained.  In  the 
distillation  explosions  very  frequently  occurred. 
There  is  also  much  danger  in  passing  acetylene  into 
heated  antimony  pentachloride.  The  reactions  of  this 
method  of  preparing  the  chlorides  of  acetylene  were 
represented  by  the  authors  by  the  following  equations  : 

C2H2  +  SbCl5=C2H2'SbCl5. 

C2H2SbCl5=C2H2Cl2  +  SbCl3. 

C2H2'SbCl5  +  SbCl5=C2H2Cl4  +  2SbCl3 

Sabanejeff  in  1883  repeated  these  experiments  of 
Berthelot  and  Jungfleisch1  in  order  to  obtain  the  di- 
chloride  of  acetylene,  and  the  intermediate  compound 
C2H2'SbCl5,  but  with  little  success.  The  absorption  of 
the  gas  took  place  with  great  difficulty,  and  with 
very  little  evolution  of  heat.  Shaking  the  contents 


1  Ann.   216,  257. 


—  8i  — 

of  the  flask  often  gave  rise  to  an  explosion.  Sabane- 
jeff  could  not  obtain  the  crystalline  compound  of 
acetylene  with  antimony  pentachloride,  though  he 
claimed  to  have  continued  the  process  a  long  time. 

Still  another  cause  assigned  for  the  phenomenon  of 
explosion  of  an  acetylene  and  chlorine  mixture  is  pro- 
posed by  Nef.1  He  supposes  that  the  decomposition 
is  due  to  the  presence  in  acetylene  of  an  impurity,  as 
Romer  thought.  The  polyacetylene  of  the  latter 
author  is  declared  by  Nef  to  be  nothing  else  than  an 
isomeric  form  of  acetylene  represented  by  the  formula 
C:CH2,  which  he  calls  acetylidene.  The  substituted 
acetylene  chloride  discovered  by  Wallach,  is  accord- 
ing to  Nef,  to  be  represented  by  the  formula  C1HC :  C 
a  derivation  of  acetylidene,  both  of  these  compounds 
being  very  unstable  and  liable  to  spontaneous  and 
violent  decomposion. 

In  1898  Mouneyrat2  threw  some  light  upon  the 
reaction  of  chlorine  and  acetylene,  and  made  a 
thorough  study  of  the  nature  of  the  explosion  that 
occurs  when  the  gases  are  mixed.  He  obtained 
acetylene  by  the  action  of  aluminium  chloride  upon 
ethylene  chloride.  By  passing  chlorine  in  the  mixture, 
the  acetylene  given  off  reacted  forming  principally 
the  symmetrical  and  unsym metrical  tetrachlor- 
ethanes.  No  explosions  were  obtained  in  this  reaction. 

The  author  proceeds  then  to  show  that  the  phe- 
nomenon of  explosion  in  the  union  of  acetylene  and 
chlorine  is  due  to  the  presence  of  oxygen.  When  the 


1  Ann.  298,  230. 

2  Bull.  Soc.  Chim.  (36,  Ser.)  XIX.,  445. 


—  82  — 

two  gases,  acetjdene  and  chlorine,  were  allowed  to 
pass  simultaneously  into  a  mixture  of  ethylene  di- 
chloride  and  aluminium  chloride,  no  explosion  occur- 
red when  proper  care  was  used  to  exclude  air  during 
the  operation.  The  spontaneous  quiet  combustion 
of  the  two  gases  could  not,  however,  be  prevented  at 
the  beginning  of  the  action,  nor  when  both  gases  were 
passed  in  too  rapidly.  An  increased  yield  of  acetylene 
tetrachloride  was  obtained  in  this  way  and  this  was 
due  to  the  direct  union  of  the  two  gases. 

The  two  gases  were  also  united  in  test  tubes  over 
distilled  water  saturated  with  salt  to  drive  out  oxygen. 
Union  again  took  place  quietly.  If  oxygen  was  in- 
tentionally put  into  a  test-tube  before  bringing  the 
"acetylene  and  chlorine  together,  a  violent  explosion 
always  occurred.  This  was  supposed  to  be  due  to  the 
formation  and  spontaneous  decomposition  of  the 
unstable  substituted  chloracetylene,  C2HC1,  discov- 
ered by  Wallach.  Mouneyrat  concludes  that  mixtures 
of  chlorine  and  acetylene  always  combine  quietly 
with  formation  of  tetrachloracetylene  in  diffuse  day- 
light, provided  that  there  be  no  trace  of  free  oxygen 
or  of  compounds  susceptible  of  giving  off  oxygen. 

The  author  also  suggests  a  method  for  the  prepara- 
tion of  tetrachloracetylene  in  the  laboratory  by 
passing  acetylene  and  chlorine  into  a  mixture  of 
ethylene  dichloride  and  aluminium  chloride.  An 
eighty  per  cent,  yield  is  obtained.  At  higher  tem- 
peratures tetrachlorethane  in  the  presence  of  alumi- 
nium chloride  is  changed  to  hexachlorethane. 

Mixed  haloid  acetylene  compounds  containing 
chlorine  have  been  obtained  in  various  ways  analo- 


—  83- 

gous  to  the  formation  of  ethylene  derivities  of  the 
halogens.  Accordingly  by  treating  a  solution  of 
iodine  trichloride  in  hydrochloric  acid  with  acetylene. 
Plimpton1  obtained  monochloriodacetylene.  Other 
chloriodides  appear  to  have  been  formed  which  are 
richer  in  chlorine  or  iodine  but  on  raising  the  tem- 
perature of  distillation,  decomposition  sets  in  with 
the  separation  of  iodine  vapor.  The  bromochloride 
of  acetylene  is  prepared  from  the  preceding  com- 
pound. It  cannot  be  prepared  pure  from  the  chloride 
of  bromine.  C2H2IBr  is  formed  when  acetylene  is 
passed  into  bromine  moniodide  in  water.  Other 
mixed  haloids  of  more  complex  formulas  may  have 
been  present  in  these  operations,  but  could  not  be 
separated  undecomposed. 

In  1883  Sabanejeff2  published  an  investigation  on 
the  mixed  haloid  derivatives  of  acetylene.  He  suc- 
ceeded in  separating  C2H2ClBr  and  C2H2Cl2Br2  by 
acting  upon  C2H2Br2  with  antimony  pentachloride. 
Sabanejeff  treated  iodine  suspended  in  water  with 
chlorine  and  then  passed  acetylene  into  the  solution. 

Results  like  those  of  Plimpton  were  obtained.  The 
compounds  C4H2C12I2  and  C2H2C13I  were  thought  to  be 
present  but  could  not  be  separated  without  decom- 
position. When  C2H2C1I  was  treated  with  alcoholic 
potash  a  gas  was  given  off  which  the  author  con- 
cluded to  be  the  explosive  C2HC1. 

!J.  Ch.  Soc.  XLI.,  392. 
2  Ann.  216,  257. 


-84- 

DIRECT    ACTION    OF    CHLORINE   GAS   ON   ACETYLENE 

GAS. 

Although  Mouneyrat  has  quite  conclusively  shown 
that  the  cause  of  explosion  between  acetylene  and 
chlorine  when  brought  together  is  referred  to  the 
presence  of  oxygen,  nevertheless  very  conflicting 
results  have  been  obtained  which  either  leave  the 
problem  more  unintelligible,  or  point  to  [other 
accompany  causes.  Results  have  been  found  that 
point  to  the  fact  that  simply  the  presence  of  oxygen  in 
diffuse  daylight  is  not  sufficient  explanation  for  the 
explosions  that  occur.  Anyone  who  has  studied  the 
results  obtained  by  various  investigators,  or  has  tried 
to  attack  the  problem  systematically  cannot  but  be 
struck  by  the  apparent  haphazard  with  which  the 
explosions  take  place.  In  the  course  of  a  single 
experiment  it  often  happens,  that  now  quiet  union 
takes  place  with  the  formation  of  addition  products 
and  again,  by  no  apparent  change  of  conditions,  the 
uniting  gases  form  substitution  products  with  violent 
explosions.  If  oxygen  be  the  sole  cause  of  explosion, 
no  explanation  has  yet  been  offered  as  to  the  nature 
of  the  action  of  this  element  in  bringing  about  the 
phenomenon.  It  has  been  suggested  that  the  substi- 
tuted acetylene,  C2HC1,  is  the  cause  of  the  violent 
decomposition  of  a  mixture  of  acetylene  and  chlorine. 
Both  Berthelot  and  Mouneyrat  have  intimated  this, 
but  no  attempt  has  been  made  to  suggest  why  this 
compound  should  be  formed  because  oxygen  is 
present,  and  why  only  acetylene  tetrachloride  is 
formed  under  other  conditions.  The  theory  holding 
that  the  substance,  C2HC1  causes  explosion  when 


—  85  — 

acetylene  and  chlorine  are  united,  is  based  on  no 
other  fact  than  that  the  compound,  C2HC1  itself  ex- 
plodes, and  that  Wallach  prepared  this  from  di- 
chloracrylic  acid.  No  one  has,  however,  shown  that 
acetylene  and  chlorine  mixture  gives  rise  to  the 
chloracetylene  refered  to,  and  there  is  no  experimental 
evidence  that  validates  the  supposition. 

If  the  presence  of  oxygen  is  sufficient  in  itself  and 
necessary  to  cause  explosion  in  a  mixture  of  acety- 
lene and  chlorine,  then  the  presence  of  oxygen  ought 
in  every  case  give  rise  to  violent  detonation  I  have 
performed  a  number  of  experiments  that  tend  to  dis- 
prove this  assumption.  I  had  undertaken  to  see 
whether  the  temperature  of  an  experiment  has  any 
connection  with  the  explosion,  but  with  what  result 
will  be  seen  in  the  course  of  this  work. 

I.  — ACETYLENE  AND  CHLORINE  HYDRATE. 

Chlorine  was  passed  into  water  surrounded  by  a 
freezing  mixture.  Frequent  shaking  was  resorted  to 
in  order  to  obtain  small  crystals  of  chlorine  hydrate. 
When  sufficient  hydrate  was  obtained  the  product 
was  transferred  to  a  beaker,  to  insure  that  no  gas 
collect  above  the  liquid  and  so  render  doubtful 
whether  any  action  that  took  place  be  the  result  of 
the  union  of  the  two  gases,  or  of  direct  combination 
with  the  hydrate.  Neither  a  slow  or  rapid  stream  of 
acetylene  caused  action  with  hydrate  itself,  neither 
in  subdued,  diffuse,  or  direct  sunlight.  No  action 
was  observed  between  the  acetylene  and  chlorine 
gases  which  escaped.  All  the  chlorine  was  driven 
out  of  solution  by  the  acetylene,  which  was  passed 


—  86  — 

into  the  hydrate  until  a  temperature  of  2 1  °  C.  was 
obtained.  No  trace  of  tetrachloracetylene  was  ob- 
tained. When  bromine  was  added  to  the  hydrate, 
the  red  color  disappeared  by  action  of  acetylene,  but 
the  chlorine  remained  or  was  eventually  drawn  out 
of  solution  without  any  apparent  action. 

Nascent  acetylene  did  not  give  different  results. 
Calcium  carbide  granulated  and  powdered,  showed 
no  chemical  action  or  explosion.  When,  however, 
the  operation  was  performed  in  closed  vessels  so  that 
both  gases  mix  above  the  solution,  explosion  took 
place  accompanied  with  separation  of  carbon.  The 
odor  of  hexachlorethane  clung  tenaciously  to  the 
particles  of  soot. 

2. —  ACTION   OF    A   SOLUTION   OF  ACETYLENE  IN  ACETONE  TO- 
WARDS A  SOLUTION  OF  CHLORINE  IN  CARBON  TETRA- 
CHLORIDE AT  LOW  TEMPERATURES. 

Another  attempt  to  unite  acetylene  and  chlorine  at 
lower  temperature  was  made  in  a  different  way. 
Acetone  at  O°  C.  dissolves  about  twenty-five  volumes 
of  acetylene.  Carbon  tetrachloride  dissolves  twenty- 
five  per  cent,  of  chlorine  at  the  same  temperature. 
Various  methods  were  used  to  unite  the  gases  in  these 
solutions.  Chlorine  was  passed  into  a  saturated 
acetone  solution  of  acetylene,  and  similarly  acetylene 
gas  into  the  chlorine  solution  of  carbon  tetrachloride. 
Spontaneous  combustion  could  not  be  avoided,  espe- 
cially in  closed  vessels.  Explosions  in  test-tubes  even 
were  very  great.  No  direct  action  took  place  within 
the  solution  in  either  case,  all  the  explosions  resulted 
from  gas  mixtures  above  the  liquid  in  the  vessels. 


-87- 

As  the  solutions  of  gases  could  not  be  poured  into 
one  another  directly  without  spontaneous  combustion, 
one  solution  was  introduced  into  the  other  slowly  by 
a  dropping  funnel  dipping  below  the  liquid.  The 
heat  of  reaction  drove  out  the  gases  from  solution 
which  then  burnt  with  separation  of  clouds  of  carbon. 
In  examining  the  products  no  tetrachloracetylene 
was  found.  The  substances  formed  were  chloracet- 
ones.  The  carbon  separated  was  mixed  with  hexa- 
chlorethane  in  small  quantity. 

DIRECT  UNION  OF  ACETYLENE  AND  CHLORINE  AT  I,OW 
TEMPERATURES. 

To  test  the  effect  of  low  temperatures  on  the  action 
of  acetylene  and  chlorine  the  gases  were,  in  another 
type  of  experiment,  passed  simultaneously  into  a  long 
wide  tube  several  inches  in  diameter.  The  operation 
was  performed  in  diffuse  daylight  on  the  window-sill 
outside,  at  a  temperature  of  .1°  to  .2°  C.  The  large 
glass  tube  was  closed  below  by  a* two-holed  rubber 
stopper.  The  chlorine  was  passed  in  by  a  smaller 
glass  tube,  and  acetylene  through  another  tube  bent 
so  as  to  dip  below  a  layer  of  water.  During  one  of 
the  experiments  the  top  of  the  apparatus  was  left 
open  so  that  access  of  air  was  not  excluded.  In 
another  experiment  the  top  of  the  larger  glass  tube 
was  connected  with  a  large  Gooch  tube  which  dipped 
below  water  in  a  beaker.  Chlorine  gas  was  first 
passed  into  the  apparatus  and  later  acetylene.  As 
soon  as  the  latter  gas  was  led  in,  dense  clouds  of 
white  fumes  appeared,  indicating  the  formation  of 
tetrachloracetylene  which  in  a  few  minutes  began  to 


—  88  — 

condense  and  trickle  down  the  sides  of  the  tube  No 
explosion  took  place,  no  separation  of  carbon  or 
spontaneous  combustion.  The  gases  that  escaped  did 
not  burn,  though  both  gases  were  passed  in  so  rapidly 
that  the  bubbles  in  the  wash-bottles  could  not  be 
counted.  After  the  gases  had  thus  been  allowed  to 
combine  for  more  than  an  hour  without  any  sign  of 
explosion  or  combustion,  more  than  30  grams  of 
tetrachloracetylene  were  formed.  At  the  end  of  one 
hour,  several  cubic  centimeters  of  air  were  introduced 
with  the  chlorine  into  the  apparatus.  No  sign  of 
explosion  or  combustion  was  noted,  and  after  another 
hour  had  elapsed  another  expedient  was  tried  to 
ascertain  the  effect  on  the  general  action.  Hitherto 
the  flow  of  gases,  though  both  very  rapid,  had  been 
nearly  equal  with  perhaps  a  slight  excess  in  volume 
of  the  chlorine.  By  quickly  and  vigorously  shaking 
the  acid  mixture  of  bleaching  powder  the  flow  of 
chlorine  gas  was  suddenly  very  much  increased. 
After  a  few  seconds  a  faint  brown  cloud  as  large  as  a 
candle  flame  began  to  form  at  the  top  of  the  large 
tube.  This  puff  of  carbon  slowly  traveled  down  the 
tube  increasing  in  size,  accelerating  in  velocity,  and 
becoming  darker  in  color  until  near  the  chlorine  tube 
it  became  a  quiet  flame.  Much  carbon  was  deposited 
at  the  lower  end  of  the  apparatus.  The  silent  explo- 
sion lasted  about  ten  seconds.  When  the  excess  of 
chlorine  had  been  used  up,  the  quiet  union  of  acety- 
lene and  chlorine  again  proceeded  with  formation  of 
tetrachlorethane. 

Another  characteristic  peculiar  to  the  phenomenon 
of  explosion  is,  that  whenever  it  occurs  it  is  accom- 


—  89- 

panied  with  the  formation  of  hexachlorethane.  The 
carbon  separated  by  explosion  seems  to  perform  some 
catalytic  function  in  substituting  the  hydrogen  atoms 
of  acetylene  with  chlorine.  During  two  hours  not  a 
trace  of  hexachlorethane  was  obtained  though  over 
30  grams  of  acetylene  tetrachloride  resulted.  During 
explosion  hexachlorethane  is  principally  formed.  If 
the  experiment  be  so  regulated  that  the  acetylene  is 
made  to  burn  in  an  atmosphere  of  chlorine  which  is 
easily  done  by  bringing  about  a  disturbance  of  the 
equilibrium  in  the  union  of  the  two  gases,  such  as  I 
have  just  referred  to,  the  hexachlorethane  is  formed 
in  sufficient  quantity  to  be  sublimed  in  clear  crystals 
from  the  carbon  mass.  It  may  be  likewise  separated 
from  the  excess  of  tetrachlorethane  by  driving  the 
latter  over  in  dry  steam.  The  tarry  mass  left  behind 
is  a  mixture  of  carbon  and  hexachlorethane  —  the 
latter  can  be  separated  with  ether  or  by  sublimation. 

Berthelot  in  attempting  to  give  an  explanation  to 
the  explosive  nature  of  acetylene  and  chlorine 
mixtures,  supposed  that  the  phenomenon  was  due  to 
the  energy  of  union,  so  much  heat  being  given  off  as 
to  cause  partial  decomposition  of  the  products  into 
hydrochloric  acid  and  carbon. 

The  formation  of  hexachlorethane  at  the  moment 
af  spontaneous  combustion  seems  to  point  to  the  fact 
that  the  explosion  of  acetylene  and  chlorine  mixtures 
is  due  to  the  energy  of  reaction  between  the  two  gases 
when  brougth  together.  Acetylene  being  an  en- 
dothermic  compound  gives  off  great  heat  in  decom- 
position when  substitution  compounds  are  formed, 
and  substitution  products  are  always  formed  during 


—  90  — 

explosion  of  mixtures  of  the  two  gases.  Even  in 
violent  decomposition  of  very  small  quantities  the 
peculiar  odor  of  hexachlorethane  noticed  after  explo- 
sion can  be  noted.  No  other  substituted  compounds 
besides  hexachlorethane  were  noticed. 4 

It  is  also  noteworthy  that  if  the  experiment  is  con- 
ducted so  as  to  obtain  continuous  combustion  of 
acetylene  and  chlorine,  little  or  no  tetrachloracetylene 
is  obtained,  but  the  carbonaceous  mass  is  rich  in 
hexachlorethane.  This  would  lead  us  to  believe  that 
the  products  of  substitution  are  obtained  according  to 
a  reaction  such  as  the  following  : 

2C2H2  +  5C12  =  C2C16  +  4HC1  +  2C. 

The  heat  given  off  in  breaking  up  a  molecule  of 
acetylene  and  also  as  a  result  of  forming  hydrochloric 
acid  would  be  sufficient  to  propagate  the  explosion  in 
the  residue  of  acetylene  and  chlorine  according  to  the 
reaction  : 

C2H2  +  C12  =  2HC1  +  2C. 

I  have  noticed,  morever,  in  the  preparation  of 
tetrabromethane  that  if  acetylene  be  allowed  to  enter 
too  rapidly  into  bromine  cooled  by  ice  water,  the 
same  phenomenon  of  spontaneous  combustion  or  total 
decomposition  with  formation  of  substitution  products 
results  owing  to  the  energy  of  reaction.  A  very 
rapid  stream  of  acetylene  will  cause  ignition  of  bromine 
vapor.  We  should  then  expect  that  chlorine  which 
is  more  energetic  than  bromine  in  its  action  would 
show  the  same  phenomenon  of  explosion  by  the 
violence  of  the  reaction.  In  fact  even  ethylene  under 
certain  circumstances  will  explode  with  chlorine 


though  not  as  energetically  as  in  the  case  of  acety- 
lene. Whatever  may  be  the  action  of  oxygen  in 
initiating,  or  helping  the  explosion  of  acetylene  with 
chlorine,  it  cannot  be  the  sole  cause  of  the  phenome- 
non, or  its  introduction  in  the  experiment  just  de- 
scribed would  have  caused  explosion.  As  a  matter 
of  fact  not  the  least  effect  resulted.  Not  until  after 
an  hour  had  elapsed  did  any  explosion  occur,  and 
then  it  was  induced  by  other  means. 

CHLORINE  AND  ACETYLENE  AT  THE  TEMPERATURE  OF  BOII,- 
ING  WATER. 

Chlorine  and  acetylene  were  brought  together  into 
a  flask  of  boiling  water  connected  with  a  condenser. 
The  latter  in  turn  was  connected  with  a  closed  receiver 
and  several  small  Wolff  flasks  containing  water  and 
dilute  caustic  potash.  After  the  water  had  been 
boiling  some  time,  chlorine  was  passed  into  the  ap- 
paratus until  the  air  was  displaced.  Acetylene  was 
then  passed  into  the  flask  and  so  regulated  as  not  to 
exceed  one-half  the  volume  of  the  chlorine  entering. 
An  increased  flow  of  acetylene  results  in  an  immediate 
appearance  of  a  flame  in  the  condenser  which  burns 
as  long  as  the  excess  of  gas  lasts.  If  the  proportion 
of  gases  be  well  regulated  no  substituted  acetylene  is 
formed.  As  soon  as  an  excess  of  acetylene  occurs,  a 
play  of  flames  is  noticed  creeping  slowly  from  the 
lower  part  of  the  condenser  to  the  point  where  the 
steam  condenses.  If  the  whole  apparatus  be  well 
filled  with  chlorine  previous  to  the  entrance  of  acety- 
lene no  explosion  takes  place.  The  flames  can  more- 
over, be  prevented  by  regulating  the  stream  of 


—  92  — 

acetylene  gas.  It  is  important  to  have  the  flow  of 
acetylene  so  regulated  that  union  takes  place  in  the 
flask  when  diluted  with  water  vapor.  The  condensed 
stream  carries  down  with  it  drops  of  an  oily  liquid 
which  was  collected,  dried,  and  distilled.  It  was 
found  to  be  tetrachloride  of  acetylene,  and  had  the 
correct  boiling  point.  A  solution  of  dilute  sulphuric 
acid  gave  similar  results  when  boiled. 

It  was  noted  that  when  acetylene  were  diluted  in 
the  steam,  no  explosion  in  the  flask  occurred.  Any 
unused  excess  reaching  the  condenser  was  inflamed 
therein.  The  play  of  flames  can  at  will  be  stopped  or 
started  by  regulating  the  flow  of  acetylene.  These 
facts  lead  to  the  supposition  that  beside  the  presence 
of  oxygen  and  the  influence  of  diffuse  daylight  as  a 
cause  of  explosion,  the  energy  of  reaction  between 
such  active  agents  as  acetylene  and  chlorine,  is  also 
a  factor  not  to  be  overlooked  in  considering  the  ex- 
plosion of  the  gases. 

ACETYLENE  AND  CHLORINE  AT  TEMPERATURES  ABOVE  IOO°  C. 

In  order  to  study  the  behaviour  of  acetylene  to- 
wards chlorine  at  temperatures  above  100°  C.  the 
gases  were  passed  into  a  retort  heated  in  an  air-bath 
to  the  desired  temperature.  The  gases  were  dried 
perfectly.  In  the  first  experiment  the  gases  were 
diluted  with  hydrochloric  acid  gas.  The  acetylene 
and  hydrochloric  acid  gas  were  passed  through  one 
tube  into  the  heated  retort,  and  chlorine  through 
another  tube.  The  air  bath  was  heated  to  230°  C. 
and  chlorine  was  then  passed  in  to  displace  the  air  in 
the  apparatus.  The  retort  was  as  usual,  connected 


—  93- 

with  a  condenser,  receiver,  and  wash-bottles  to  re- 
move any  products  formed.  Under  these  conditions 
union  of  these  gases  took  place  quietly,  neither 
explosion  or  flames  were  noticed  though  the  opera- 
tion lasted  all  day.  The  interior  of  the  retort  was 
found  however,  to  contain  considerable  deposit  of 
carbon  which  was  also  swept  down  the  jacket  of  the 
condenser ;  thus  indicating  that  quiet  combustion  had 
taken  place  in  the  dark.  About  100  grams  of  tetra- 
chloracetylene  were  obtained.  It  boiled  at  147°  C. 
A  considerable  amount  of  hexachlorethane  was  also 
found.  It  was  removed  by  separating  the  tetrachlor- 
ethane  with  steam  and  extracting  the  black  residue 
with  ether.  After  evaporating  the  ether  the  crystals 
were  sublimed.  The  yield  of  oil  was  not  so  good  as 
when  uniting  the  gases  in  the  cold.  I^ess  oil  was 
obtained  in  proportion  to  the  amount  of  acetylene 
and  chlorine  used,  and  the  duration  of  the  process. 

An  experiment  similar  to  the  preceding,  performed 
at  a  temperature  of  140°  C.  gave  nearly  the  same  re- 
sults. The  acetylene  was  not  diluted  with  dry  hydro- 
chloric acid  acid.  The  gases  were  passed  into  the 
retort  through  separate  tubes  in  the  proportion  of  one 
volume  of  acetylene  to  a  little  more  than  two  volumes 
of  chlorine.  The  retort  in  the  air-bath  was  connected 
with  a  condenser  with  closed  receiver,  and  several 
Wolff  flasks  containing  water  and  caustic  potash. 
Chlorine  was  passed  into  the  apparatus  first,  and  then 
acetylene.  After  some  time  carbon  was  carried  over 
into  the  inner  tube  of  the  condenser  which  became 
gradually  coated.  No  explosion  of  flames  were 
noticed.  The  flow  of  chlorine  was  then  suddenly  in- 


-94  — 

creased  in  volume,  with  the  result  that  a  play  of 
flame  was  seen  within  the  condenser,  beginning  at 
the  bottom  and  passing  slowly  to  the  point  of  conden- 
sation where  it  continued  to  burn  brightly  until  the 
excess  of  chlorine  was  used  up.  This  sudden  dis- 
turbance of  the  equilibrium  of  the  uniting  gases 
resulted,  as  in  the  other  experiments,  in  the  forma- 
tion of  substitution  products. 

As  soon  as  the  gases  were  again  regulated  carefully 
the  formation  of  tetrachlorethane  continued  quietly 
throughout  the  greater  part  of  the  day  until  the 
operation  was  finished.  The  products  of  reaction 
were,  as  in  the  previous  experiment,  tetrachlorethane 
and  hexachlorethane. 


—  95  — 


ACTION  OF  ACETYLENE   TOWARDS  CHLO- 
RIDES AND  CHLORINATING  AGENTS. 


REATION    OF  SULPHURYI,   CHDORIDK   WITH    UNSATU- 
RATED  ALIPHATIC   HYDROCARBONS. 

Unlike  the  other  oxy-chlorides,  sulphuryl  chloride 
is  principally  a  chlorinating  agent.  This  action  of 
chlorination  takes  place  in  many  instances  by  the 
dissociation  of  the  compound  into  its  derivative  com- 
ponents, sulphur  dioxide  and  chlorine,  both  being 
present  in  the  nascent  state  at  the  moment  of  reaction. 
Many  substances  susceptible  of  union  with  the 
halogens  can  accordingly  take  from  sulphuryl  chloride 
its  chlorine,  which  are  not  ordinarily  or  readily 
capable  of  being  effected  in  other  ways.  In  some 
instances  the  operation  takes  place  by  direct  combina- 
tion, in  other  cases  the  addition  of  aluminium  chloride 
is  necessary  as  an  intermediary  for  the  reaction. 

Sulphuryl  chloride  has  been  used  mostly  to  effect 
reactions  in  the  aromatic  series,1  and  here  it  manifests 
its  general  property  of  substituting  its  halogen  in  the 
place  of  one  or  more  hydrogen  atoms  of  those  com- 

1  Ber.  15,  1736.  Bberhard,  Inaug.  Dissert,  p.  13.  (Zi866, 
705.)  Eberhard,  Diss.  p.  n.  Ber.  n,  567,  J.  Pr.  II.,  17,  322. 
Wenghofer,  Inaug.  Dissert.  Rostock,  1894. — Ber.  26,  2940. 
Fram,  Inaug.  Dissert.  Rostock,  1895.  Gaz.  XXX.,  i,  572. 
Gaz.  XXXII.,  II.,  30.  Gaz.  XXVI.,  II.,  403,  (1896.)  Gaz. 
XXIV.,  I.  p.  236,  (1894.)  Ber.  26,  2940.  Gaz.  XXVIII.,  I. 
197.  Gaz.  XXVIII.,  I.,  197,  1898.  Gaz.  XXIX.,  I.,  340,  371, 
383.  Gaz.  XXIX.,  I.,  554.  Gaz.  XXXI.,  I.,  464.  Gaz.  XXXI., 
II.,  184. 


—  96  — 

pounds.  With  salts  or  their  acids  it  behaves  like  the 
chlorides  of  phosphorus,  the  hydroxyl  being  replaced 
with  the  formation  of  acid  chlorides. 

The  chlorination  of  inorganic  substances  has  been 
shown  to  be  accelerated  by  the  addition  to  sulphuryl 
chloride  of  some  aluminium  chloride.  This  increase 
of  activity  is  ascribed  to  the  power  possessed  by  the 
aluminium  chloride  of  dissociating  the  sulphuryl 
chloride  into  its  component  gases,  both  being  present 
in  the  nascent  condition  when  a  substance  is  added 
that  is  capable  of  being  united  either  to  the  chlorine 
or  to  the  sulphur  dioxide.  The  action  of  the  alumi- 
nium chloride  in  this  reaction  is  somewhat  different 
from  its  action  in  the  ordinary  cases  in  which  it  is 
used  as  an  agent  for  chlorinatian  or  condensation  of 
hydrocarbon  residues.  Ordinarily  the  action  of  alumi- 
nium chloride  seems  to  be  that  of  forming  a  compound 
with  a  hydrocarbon  or  an  acid  chloride.  This  double 
compound  breaks  down  an  addition  of  water,  and  two 
hydrocarbon  or  a  hydrocarbon  and  a  ketone  residues 
unite  together.  In  case  of  chlorination,  one  of  the 
atoms  in  the  chlorine  molecule  unites  with  the  hy- 
drocarbon residue  while  the  other  is  joined  to  the 
hydrogen  atom  abstracted  from  the  hydrocarbon  to 
form  hydrochloric  acid  which  is  evolved  in  the  process 
of  decomposition  with  water. 

Andrianowsky2  in  1879  discovered  that  aluminium 
chloride  absorbs  sulphur  dioxide  to  form  a  compound 
to  which  he  ascribed  the  formula,  A1C1'2SO2C1.  This 
is  syrupy  liquid  that  solidifies  at  10°  C.  to  a  crystal- 
line mass.  On  heating  it  attains  the  consistency  of 
anhydrous  glycerine.  On  further  heating  it  decom- 


—  97  — 

poses  giving  off  sulphur  dioxide,  and  disulphur  di- 
chloride  in  small  quantity,  while  aluminium  chloride 
and  some  aluminium  sulphate  are  left.  It  is  com- 
pletely decomposed  at  140°  C. 

Now  Ruff1  has  shown  that  when  sulphuryl  chloride 
dissolves  aluminium  chloride  the  compound, 
A1C12' SO2C1,  is  formed,  and  on  heating  the  solution, 
can  be  obtained  at  the  end  of  the  operation.  It  is 
supposed  to  be  present  even  at  ordinary  temperatures 
being  formed  according  to  the  reversible  reaction  : 

A1C13  +  SO2C12±=^A1C13'SO2  +  C12. 

He  shows  that  the  compound  of  aluminium  chloride 
and  sulphur  dioxide  is  formed. 

It  is  then  concluded  that  a  real  catalytic  action  in 
the  older  sense  of  the  word,  occurs  here  ;  for  a  single 
addition  of  a  small  quantity  of  aluminium  chloride  is 
sufficient  to  effect  the  chlorination  of  an  indefinite 
amount  of  sulphur,  by  starting  an  accelerated  action 
in  the  mixture  at  ordinary  temperature. 

In  the  action  of  aluminium  chloride  with  sulphuryl 
chloride,  the  end  products  are  obtained  by  reason  of 
the  formation  of  the  substance  A1C13'SO2,  or  rather 
because  of  the  affinity  between  aluminium  chloride, 
A1C13,  and  sulphur  dioxide  when  any  compound  present 
is  capable  of  forming  a  stable  chloride.  The  substance 
A1C13*SO2  is,  however,  only  a  bye-product.  The  chlori- 
nation is  effected  by  reason  of  the  tendency  of  aluminium 
chloride  to  dissociate  sulphuryl  chloride,  and  unite 
with  the  sulphur  dioxide  given  off.  This  action  of 


lBer.  35,  4453,  (1903.) 
2  Ber.  12,  688,  853. 


-98- 

influence  of  aluminium  chloride  in  breaking  up  the 
sulphuryl  chloride  molecule  has  been  called  by  Ruff 
"dissociation  catalysis."  The  differences  discussed 
can  be  summed  up  by  saying  that  in  the  general 
aluminium  chloride  reactions,  double  compounds  are 
formed  which  are  afterwards  decomposed  with  water. 
In  the  other  instance,  the  aluminium  chloride  instead 
of  uniting  with  sulphuryl  chloride  breaks  it  up  to 
form  the  compound  A1C13'SO2,  while  nascent  chlorine 
is  set  free.  This  action  will  be  well  illustrated  by  the 
experiments  about  to  be  described,  namely ;  the 
chlorination  of  acetylene,  ethylene,  and  amylene  in 
the  presence  of  aluminium  chloride,  by  means  of  sul- 
phuryl chloride. 

The  chlorination  of  unsaturated  hydrocarbons  seems 
to  bring  out  the  nature  of  the  theory  of  RufF  very 
strikingly  as  addition  products  are  formed.  The 
dissociated  chlorine  unites  directly  with  the  hydro- 
carbon to  form  saturated  compounds.  The  ordinary 
chlorination  reactions  of  hydrocarbons  of  saturated 
series  in  the  presence  of  aluminium  chloride  are 
operations  of  substitution  and  hydrochloric  acid  is 
evolved.  With  unsaturated  compounds  such  as  ethy- 
lene, and  acetylene,  hydrochloric  acid  is  not  formed 
but  direct  union  takes  place  with  one  or  or  more 
whole  molecules  of  chlorine  according  to  the  number 
of  uncombined  valencies  of  the  hydrocarbon  in 
question. 

By  far  the  greatest  amount  of  work  with  sulphuryl 
chloride  as  a  chlorinating  agent  has  been  done  in  the 
aromatic  series  of  the  hydrocarbons.  A  number  of 
interesting  reactions  have  of  late  been  effected  with 


—  99  — 

inorganic  compounds.  Very  few  substances  in  the 
aliphatic  series  have  as  yet  been  treated  with  sul- 
phuryl  chloride  though  the  side  chains  of  aromatic 
compounds  have  been  chlorinated  in  direct  sunlight. 
Allihn1  tried  the  reaction  of  sulphuryl  chloride  on 
acetone  and  acetoacetic  ether,  and  he  obtained  mono- 
and  di-substitution  products.  Roubleff2  succeeded  in 
chlorinating  methylacetoacetic  ether  to  a  monosubsti- 
tution  derivative  by  using  the  proper  proportions  of  re- 
agent. Glacial  acetic  acid3  gives  small  quantities  of 
acetyl  chloride  in  the  preparation  of  sulphuryl  chloride 
according  to  the  method  of  Melsens.  The  principal 
bye-product  however,  is  monochloracetic  acid.  Boiling 
glacial  acetic  acid  gives  more  acetyl  chloride  when 
treated  with  sulphuryl  chloride.  When  succinimide 
is  heated  in  sealed  tubes  to  100°  C.  dichlormaleic  acid 
imide  is  formed  which  gives  rise  to  dichlormaleic 
acid  when  dilute  alkalies  are  added.  Behrend4  ob- 
tained from  alcohol  and  sulphuryl  chloride  according 
to  the  conditions  of  the  experiment  and  the  quantities 

O  TT  O 

of   reagent  used,  the  compounds     2    Qt>SO2,    and 

QH'O  >S°2' Glyco1  gave  thesubstance  C*H*<  QSK)2C1 
The  amines  and  their  chlorides  give  respectively  sul- 
phones  or  sulphone  chlorides  of  the  corresponding 
substituted  ammonia.  Piperidine5  gives  rise  to  sul- 

1  Eberhard,  Inaug.  Dissert.  Rostock.  1894. 

2  Ann.  259.  254. 

8  Eberhard,  Inaug.  Dissert.  Rostock,  1894. 

4  Ber.  17,  9.  Ann.  222,  116,  136. 

5  Fram.  Inaug.  Dissert.  Rostock,  1895. 


too 


phopiperidid.  Mercaptan1  with  sulpliuryl  chloride 
yields  as  a  final  product,  after  separation  of  hydro- 
chloric acid  and  sulphur  dioxide,  ethyl  disulphide 

C  H  *S 

25    •      Sodium  mercaptide  was  used  instead  of  the 
C2H5*S. 

alcohol. 

The  sulphuryl  chloride  used  in  the  following 
experiments  was  obtained  from  several  sources.  Some 
was  made  according  to  the  method  of  Melsens,2  an- 
other product  was  made  by  the  method  of  Schultz,3 
finally,  sulphuryl  chloride  obtained  from  Kahlbaum 
was  used.  In  every  case  the  same  results  were 
obtained  in  the  final  reactions,  yet  in  some  instances 
the  yield  of  product  was  smaller  owing  to  the  presence 
of  impurities  that  reacted  with  aluminium  chloride 
directly,  and  thus  retarted  its  catalytic  action. 

CHI.ORINATION  OT?  ACETYLENE  WITH  SULPHURYI.  CHLORIDE 
IN  THE  PRESENCE  OF  ALUMINIUM  CHORIDE. 

As  none  of  the  aliphatic  hydrocarbons  have  as  yet 
been  treated  with  sulphuryl  chloride,  no  conclusion 
can  be  drawn  whether  any  difference  of  action  might 
be  found  between  the  behaviour  of  saturated  and  un- 
saturated  compounds  of  the  series.  The  object  of  the 
investigations  about  to  be  described,  is  the  action  of 
sulphuryl  chloride  upon  the  lower  members  of  the 
unsaturated  paraffines,  ethylene,  and  also  upon  ethy- 
lene  and  amylene. 


1  Ber.  1 8,  3178. 

2  C.    R.    76,   92,   also     Eberhard,    Inaug.    Dissert,    p.     8, 
Rostock,  1894. 

3J.  Pr.  Ch.  23,  351.     Ber.  14.  989,  2225. 


101 


Perfectly  dry  acetylene  does  not  react  with  sul- 
phuryl  chloride  at  ordinary  temperature.  The  gas 
was  passed  into  the  chloride  for  a  whole  day  without 
the  faintest  trace  of  reaction.  Even  when  the  con- 
tents of  the  flask  were  raised  to  boiling  temperature, 
no  better  results  were  perceived.  If,  however,  a  small 
amount  of  aluminium  chloride  be  added  to  the  sul- 
phury 1  chloride,  the  action  is  soon  made  manifest  by 
the  heat  evolved,  or  the  more  or  less  complete  absorp- 
tion of  the  acetylene  passed  in.  The  contents  of  the 
flask  were  decomposed  by  being  poured  slowly  into 
water  at  low  temperature,  and  a  liquid,  having  the 
ethereal  odor  of  chloroform  was  left  behind.  There 
were  likewise  traces  of  evil-smelling  sulphur  com- 
pounds. These  latter  reminded  one  forcibly  of  a 
mixture  of  mercaptan  and  mustard  oil.  The  residue 
of  organic  oil,  after  standing  under  water  for  some 
twelve  hours  and  being  washed  with  dilute  caustic 
potash  solution  and  then  with  water,  was  dried  over 
calcium  chloride  and  distilled.  The  contents  of  the 
distilling  flask  went  over  at  a  temperature  ranging 
from  120°  C.  to  1 60°  C.  then  decomposition  set  in 
accompanied  with  the  appearance  of  white  fumes  and 
the  separation  of  carbon  in  a  hard  gritty  mass.  Most 
of  the  oil  boiled  between  1 40°  to  1 45°  C.  (uncorrected. ) 
Not  the  least  trace  of  sulphur  was  found  in  the  latter 
fraction.  Though  the  material  used  for  distillation 
was  quite  small,  it  was  evident  that  the  principal 
product  was  tetrachloracetylene,  whose  boiling  point 
is  147°  C. 

In  accordance  with  the  conclusions  arrived  at  by 
Ruff,  it  is  evident  that  the  action  of  aluminium  chlo- 


—  IO2  — 

ride  in  the  presence  of  sulphuryl  chloride  is  to 
accelerate  the  operation  by  bringing  about  chemical 
dissociation.  If,  however,  chlorine  were  present  in 
the  free  state,  we  should  expect  according  to  the 
results  arrived  at  in  the  preceding  work,  that  when 
acetylene  were  passed  into  the  solution  of  sulphuryl 
chloride,  explosions  w@uld  occur.  The  acetylene, 
however,  was  chlorinated  to  tetrachlorethane  without 
even  the  phenomenon  of  spontaneous  combustion. 

It  was  noted  that  in  the  previous  experiment  the 
yield  of  chloride  of  acetylene  seemed  to  bear  some  re- 
lation to  the  amount  of  aluminium  chloride  used, 
since  only  a  small  amount  of  the  oil  was  obtained  even 
after  passing  acetylene  gas  into  the  mixture  for  many 
hours.  It  was  supposed  that  a  double  compound 
with  aluminium  chloride  is  formed  which  is  decom- 
posed by  water,  one  of  the  products  being  tetra- 
chloracetylene.  Accordingly,  about  150  grams  of 
aluminium  chloride  were  added  to  250  grams  of  sul- 
phuryl chloride,  in  order  to  insure  complete  and  rapid 
decomposition  at  ordinary  temperature.  The  appara- 
tus used,  consisted  of  a  round-bottom  flask  fitted  with 
a  two-holed  stopper,  one  hole  for  a  reflux  condenser,  the 
other  for  a  glass  tube  through  which  the  acetylene 
was  introduced.  The  acetylene  was  obtained  from  an 
ordinary  dip-generator,  and  was  dried  by  passing 
through  concentrated  sulphuric  acid  in  a  wash-bottle. 
To  insure  complete  separation  of  moisture  it  was  next 
passed  through  a  drying  cylinder  containing  pieces  of 
calcium  carbide  of  the  size  of  a  pea.  In  this  way  very 
rapid  streams  of  acetylene  can  be  effectually  dried 
and  the  traces  of  acid  carried  over  from  the  wash- 


-103- 

bottle  of  sulphuric  acid  are  also  removed  by  the 
carbide. 

In  thus  passing  acetylene  into  the  mixture  of 
sulphuryl  chloride  and  aluminium  chloride  the  con- 
tents, according  to  the  theory  of  Ruff,  ought  to  be 
strongly  dissociated  by  the  gas,  especially  when  a 
rapid  stream  is  allowed  to  enter.  No  particular  care 
was  used  to  exclude  air.  In  fact  air  was  purposely 
introduced  and  no  explosion  was  ever  found  to  take 
place.  Even  when  heated  on  a  water-bath  while  the 
gas  was  being  passed  into  the  mixture,  no  sign  of 
explosion  or  combustion  was  observed.  This  fact  is 
noteworthy  because  as  Ruff  has  shown,  free  chlorine 
is  evolved  even  at  moderate  heat. 

It  was  found  that  it  is  not  necessary  to  heat  the 
sulphuryl  chloride  and  aluminium  chloride  to  obtain 
reaction.  In  fact,  much  heat  is  evolved  and  after 
passing  the  gas  into  the  mixture  some  minutes,  the 
contents  of  the  flask  became  quite  warm.  Ordinarily, 
with  small  amounts  of  substance  no  cooling  need  be 
resorted  to,  but  this  may  be  made  necessary  as  de- 
composition products  are  formed  when  the  heat  is  too 
great.  The  mixture  becomes  dark  purple  or  even 
black.  When  the  flask  is  moderately  warmed  by  the 
heat  of  reaction,  the  acetylene  is  absorbed  as  fast  as  it 
can  be  brought  into  the  apparatus.  The  contents 
ought  not  to  be  allowed  to  take  on  a  darker  hue  than 
auburn  or  brown.  After  some  time  the  heat  of  reac- 
tion slackened  and  the  absorption  ceased.  The 
experiment  had  lasted  five  hours.  The  contents  of 
the  flask  were  then  poured  into  several  liters  of  cold 
water.  With  constant  stirring  the  decomposition 


—  104  — 

could  be  rather  quietly  effected.  A  clear  amber- 
colored  oil  separated  at  the  bottom  of  the  vessel,  and 
at  the  same  time  white  fumes  were  given  off  during 
the  operation.  A  most  penetrating  and  disagreeable 
odor  was  perceived.  The  fumes  also  effected  the  eyes  so 
powerfully  as  to  make  it  impossible  to  perform  the 
work  except  in  a  well  ventilated  hood.  A  painful 
flow  of  tears  was  caused  by  the  least  trace  of  sub- 
stance decomposed.  The  following  day  the  irritation 
to  the  eyes  and  the  mustard  oil  smell  was  less 
noticeable  owing,  probably,  to  the  fact  that  the 
compound  is  decomposed  on  standing  some  time  with 
water.  The  clear  heavy  oil  obtained,  was  washed 
with  dilute  caustic  potash  solution  to  remove  acid 
traces.  It  was  then  shaken  with  distilled  water, 
dried  over  fused  sodium  sulphate,  and  part  dried  over 
fused  calcium  chloride.  The  principal  fraction  of  the 
product  boiled  at  147°  C.,  and  as  no  trace  of  sulphur 
could  be  found  by  analysis,  it  was  concluded  to  be 
tetrachloracetylene.  It  possessed  an  ethereal  odor 
like  chloroform  mixed,  however,  with  traces  of  the 
odor  of  mustard  oil. 

When  acetylene  is  passed  into  the  solution  or 
mixture  of  aluminium  chloride  and  sulphuryl  chloride, 
action  takes  place  almost  immediately.  Under 
favorable  conditions  the  dry  gas  is  completely 
absorbed  as  fast  as  it  can  conveniently  be  passed  into 
the  apparatus.  The  heat  is  considerable,  and  no 
gaseous  products  are  evolved.  If  the  acetylene 
leaving  the  reflux  condenser  is  passed  into  water, 
a  strong  smell  of  sulphur  dioxide  is  noted.  This, 
however,  is  due  to  the  decomposition  by  water  of  the 


-  105  — 

sulphury  1  chloride  carried  over  mechanically,  even 
through  a  well  cooled  condenser.  The  gas  passed 
into  barium  chloride,  gives  rise  to  an  immediate 
precipitate  insoluble  in  acids,  barium  sulphate. 
Moreover,  when  the  action  has  well  started,  the 
reflux  condenser  may  be  stopped  with  a  cork,  so 
that  no  escape  for  the  evolved  acetylene  is  possible. 
It  is  still  absorbed  in  a  regular  stream  and  without 
the  production  of  any  gaseons  product. 

When  acetylene  is  made  to  react  with  suphuryl 
chloride  in  the  presence  of  aluminium  chloride,  the 
principal  product  has  been  shown  to  be  an  addition 
product  acetylene  tetrachloride.  No  other  chloride 
has  been  separated  by  fractional  distillation,  but 
there  is  evidently  another  compound  present  that 
possessed  the  irritating  odors  just  mentioned.  More- 
over, on  heating  the  acetylene  tetrachloride  residues, 
the  temperature  rose  steadily  until,  at  a  certain  point 
between  165°  C.  and  175°  C.,  decomposition  set  in, 
accompanied  with  the  separation  of  carbon  and 
evolution  of  hydrochloric  acid  gas.  The  last  frac- 
tions also  gave  evidences  of  the  presence  of  sulphur. 
In  order  to  isolate  the  sulphur  compound  other 
methods  beside  that  of  fractional  distillation  had  to 
be  resorted  to.  In  the  action  of  sulphuryl  chloride 
on  various  products,  other  compounds  beside  chlorides 
have  been  obtained,  such  as  sulphones,  sulphone 
chlorides,  even  in  one  instance  a  disulphide.  It  was 

thought  probable  that   beside    tetrachlorethane,    a 

/•ATT  /o/~)  rM^ 
sulphone    chloride    of   the    formula     A-ripi 

might  exist  in  the  products  of  reaction.     This  sub- 


—  io6  — 

substance  would  bear  a  relation  of  acid  chloride  to 
acetaldehyde  disulphonic  acid  as  ethylidene  chloride 
itself  does  to  acetaldehyde. 

In  order  to  purify  the  tetrachlorethane  obtained 
from  sulphuryl  chloride,  the  compound  was  driven 
over  by  distillation  in  a  current  of  dry  steam.  The 
oil  thus  obtained  lost  much  of  its  evil  odor,  while  a 
semi-solid  brownish  residue  was  left  in  the  distilling 
flask.  This  product  could  not  be  purified  sufficiently 
to  be  analyzed.  It  is  some  what  soluble  in  ether, 
insoluble  in  ordinary  alcohol,  but  could  not  be 
crystallized  in  a  mixture  of  ether  and  alcohol.  All 
attempts,  to  obtain  crystals,  or  any  definite  compound 
failed.  The  tetrachloracetylene  thus  purified,  boiled 
at  145°  C. — 148°  C.,  and  posessed  a  nearly  pure  odor 
of  chloroform.  As  the  temperature  rose  above 
148°  C.  — 150°  C.,  signs  of  decomposition  appeared 
in  the  presence  of  white  fumes  and  separation  of 
carbon.  The  brownish  residue  when  cooled,  de- 
posited crystals  more  or  less  clear.  Only  a  very 
small  amount  was  obtained.  They  were  recrystallized 
in  a  few  drops  of  ether  when  separated  from  the  oily 
residue.  Analysis  gave  no  trace  of  sulphur ;  they 
posessed  the  characteristic  camphor-like  odor  of 
hexachlorethane.  They  were  formed  from  the 
chlorination  of  tetrachlorethane  in  the  presence  of 
aluminium  chloride. 

C2H2C14+S02C12+ A1C1,= C2C16+ AlClg  *SO2+  2HC1. 

Another  attempt  was  made  to  isolate  the  sulphur 
compounds  referred  to.  About  seven  hundred  grams 
of  chemically  pure  sulphuryl  chloride  were  treated 


-107- 

with  acetylene  in  the  presence  of  aluminium  chloride 
in  portions  of  two  hundred  to  two  hundred  and  fifty 
grams  at  a  time.  Aluminium  chloride  was  added 
during  the  operation  only  as  fast  as  it  was  dissolved 
by  the  sulphuryl  chloride.  It  was  found  that  the 
action  ceased  when  aluminium  chloride  had  been 
added  in  the  proportion  of  one  part  of  this  compound 
to  every  two,  or  two  and  half  of  sulphuryl  chloride 
by  weight. 

The  products  of  reaction  were  united  and  subjected 
to  distillation  on  a  water-bath  under  diminished 
pressure,  in  order  to  remove  the  excess  of  sulphuryl 
chloride.  About  fifty  to  seventy-five  cubic  centi- 
meters of  distillate  were  obtained.  Before  this  dis- 
tillation the  small  excess  of  aluminium  chloride  had 
had  been  removed  by  filtering  through  glass-wool. 
A  part  of  the  product  of  reaction  of  acetylene  on  the 
solution  of  aluminium  chloride  and  sulphuryl  chloride 
solidified  to  an  amorphous  mass  on  standing  several 
months. 

Under  diminished  pressure  of  58  to  63  cm. ,  the  boil- 
ing of  the  contents  of  the  flask  began  at  15°  C. 
Together  with  the  excess  of  sulphuryl  chloride  an 
oil  came  over  which  was  afterward  found  to  boil  at 
120°  C.  under  atmospheric  pressure.  It  had  the 
odor  of  chloroform,  or  ethylene  chloride,  and  posessed 
no  trace  of  any  disagreeable  products.  The  tempera- 
ture of  the  distillation  was  kept  near  80°  C.  under 
diminished  pressure,  and  when  the  product  ceased  to 
come  over,  the  operation  was  interrupted. 

The  residue  from  the  distillation  under  diminished 
pressure  was  then  decomposed  by  pouring  it  into  ice- 


—  io8  — 

water  slowly  with  constant  stirring.  No  violent 
action  took  place  under  these  circumstances.  An 
amber-colored  oil  sank  to  the  bottom  of  the  beaker. 
It  possessed  the  disagreeable  odor  already  referred  to. 
The  oil  was  distilled  in  a  current  of  steam,  and  when 
the  tetrachloracetylene  had  been  driven  over,  a  brown 
viscous  oil  was  left  in  the  distilling  flask.  This 
product  became  semi-solid  on  cooling,  but  it  resisted 
all  attempts  at  purification.  It  was  found  to  be 
soluble  in  ether,  and  when  this  was  evaporated  the 
mass  was  left  as  impure  as  before.  It  does  not 
dissolve  in  alcohol,  nor  would  it  crystallize  from  a 
mixture  of  ether  and  alcohol. 

Distillation  in  a  current  of  dry  steam  did  not,  how- 
ever, remove  the  evil  smelling  product  completely 
from  the  distillate.  The  oil  in  the  receiver  was 
thoroughly  washed  with  water,  and  finally  dried  over 
fused  sodium  sulphate.  The  product  was  subjected 
to  fractional  distillation,  and  the  greater  part  came 
over  near  147°  C.  and  proved  to  be  tetrachloracety- 
lene. Another  fraction  boiled  quite  constantly 
between  160°  C.  and  163°  C.  All  the  fractions,  even 
those  with  the  lowest  boiling  points,  possessed  the 
smell  of  mustard  oil,  and  sulphur  was  found  in 
analysis.  When  decomposition  began  at  170°  C. 
the  operation  was  stopped.  The  residue  possessed 
the  unbearable  odor  of  allyl  mustard  oil. 

The  oils  were  at  last  separately  washed  with  a 
dilute  solution  of  caustic  potash.  The  solution  took  on 
yellowish  tint  and  considerable  heat  was  evolved. 
Each  fraction  diminished  very  much  in  volume.  All 
the  fractions  were  then  separately  redistilled  and 


—  109  - 

found  to  have  the  same  boiling  point  as  before.  The 
wash  water  was  evaporated  down  on  a  water-bath, 
and  after  potassium  chloride  had  come  out,  an  impure 
salt  of  a  sulphonic  acid  crystallized  out.  It  was  not 
acetaldehyde  disulphonic  acid  as  its  oxime  could  not 
be  prepared.  The  salt  is  but  slightly  soluble  in  ether 
which  removes  all  impurities.  A  very  small  amount 
was  thus  obtained  pure  by  recrystallization  from 
alcohol.  Not  enough  was  obtained,  however,  for 
analysis. 

The  oils  after  repeated  fractional  distillation  re- 
mained constant  only  at  the  boiling  point  of  tetra- 
chlorethane.  They  seemed  to  be  purer  than  before, 
but  the  fractions  that  came  over  at  higher  tempera- 
tures still  possessed  the  odor  of  mustard  oil.  Tetra- 
chloracetylene  could  with  certitude  be  shown  to  be 
present.  The  fraction  coming  over  under  diminished 
pressure,  as  also  part  of  the  decomposed  oil,  both  of 
which  products  boil  very  constantly  at  120°  C.  were 
very  probably  tetrachlorethylene  obtained  by  decom- 
position of  tetrachloracetylene  in  the  presence  of 
aluminium  chloride  and  sulphuryl  chloride  with 
application  of  heat. 

C2H2Cli+S02Cl+AlCl3=C2CU+2HCl+AlCVSO2. 

At  1 60° — 163°  C.,  a  considerable  fraction  was  ob- 
tained with  a  remarkably  constant  boiling  point. 

According  to  the  theory  of  dissociation  catalysis 
advocated  by  Ruff,  it  is  supposed  that  sulphuryl 
chloride  is  dissociated  in  the  presence  of  aluminium 
chloride  as  represented  by  the  equation. 

AlCl3-f  S02C12^=±  A1C13 '  SO5+  C12. 


—  no  — 

A  solution  of  aluminium  chloride  in  sulphuryl 
chloride  was  put  into  a  flask  connected  with  a  well 
cooled  reflux  condenser.  The  latter  was  in  turn 
connected  with  a  long  tube  bent  at  right  angles  and 
entering  another  flask  into  which  acetylene  was 
passed.  The  last  flask  was  connected  with  a  con- 
denser and  receiver.  Twenty-five  grams  of  sulphuryl 
chloride  and  twenty  grams  of  aluminium  chloride 
were  thus  treated  to  demonstrate  the  presence  of  free 
chlorine.  If  this  gas  be  given  off,  it  would  be  shown 
either  by  its  union,  or  explosion  with  acetylene  in 
the  second  flask.  It  was  found  that  considerable 
heat  was  required  before  the  presence  of  free  chlorine 
could  be  detected  by  its  color  and  odor.  A  few  drops 
of  tetrachloracetylene  were  obtained  from  the  union 
of  the  two  gases.  By  heating  the  aluminium  chloride 
mixture  in  the  first  flask  chlorine  was  freely  evolved 
and  met  the  acetylene  in  the  second  flask.  Vapors 
of  chloride  were  effectually  kept  back  by  the  conden- 
ser. No  explosion  was  obtained  and  no  precautions 
were  made  to  avoid  one.  Acetylene  was  allowed  to 
enter  the  apparatus  before  the  chlorine  was  evolved, 
contrary  to  the  usual  method  of  bringing  the  gases 
together.  In  the  case  of  acetylene,  the  first  part  of 
the  supposed  reversible  reaction  was  found  to  hold 
good,  and  the  presence  of  tetrachlorethane  is  due  to 
the  union  of  acetylene  with  the  dissociated  chlorine 
of  the  compound,  while  the  sulphur  dioxide  unites 
with  the  aluminium  chloride. 

SO2C12+A1C18=A1C13-SO2+C12, 
2C12+C2H2=C2H2CU. 


v^r™~E^\ 

UNIVERSITY  I 


In  order  to  satisfy  myself  as  to  the  assumed  rever- 
sibility of  the  reaction  of  the  dissociation  of  sulphuryl 
chloride,  I  have  tried  to  effect  the  same  experimentally. 
It  appears  that  in  order  to  demonstrate  the  fact,  the 
attempt  should  have  been  made  to  unite  chlorine 
with  the  compound,  A1C13*SO2  to  form  sulphuryl 
chloride. 

A1C13'SO2+C12=A1C13+SO2C12. 

Unless  under  certain  conditions  this  can  be  actually 
effected,  it  cannot  be  assumed  that  the  equation  is 
reversible.  It  was  found  impossible  to  effect  a  reac- 
tion between  chlorine  and  the  compound,  A1C13'SO2, 
though  it  was  tried  in  several  ways  and  under  varied 
conditions.  Neither  at  ordinary  temperature  nor 
with  the  aid  of  heat  have  I  been  able  to  obtain  any 
sulphuryl  chloride.  Until  sulphuryl  chloride  shall 
have  been  made  from  the  substance,  A1C13*SO2,  and 
and  free  chlorine,  it  does  not  seem  justifiable  to 
postulate  the  reversible  action. 


A1C13+SO2C12=A1C13'SO2  +  C12,  or, 
C12+A1C13-SO2=A1C13+SO2C12. 

Moreover,  the  theory  of  Ruff  seems  just  as  valid 
without  assuming  that  the  action  is  reversible. 
Reversibility  is  unnecessary  to  explain  the  facts. 
It  is  sufficient  that  aluminium  chloride  dissociates 
sulphuryl  chloride  in  the  presence  of  a  third  sub- 
stance capable  of  forming  a  more  stable  chloride. 
Under  these  conditions  chlorination  will  take  place 
often  without  raising  the  temperature  by  external 
heating. 


112  — > 

In  chlorinating  acetylene  with  sulphuryl  chloride 
in  the  presence  of  aluminium  chloride,  no  explosion 
or  spontaneous  combustion  was  ever  noted,  though 
no  precautions  were  used  in  excluding  air  or  direct 
sunlight.  It  has  been  shown  that  chlorine  is  present 
even  at  ordinary  temperatures  in  the  mixture  of 
aluminium  chloride  and  sulphuryl  chloride.  I  have 
passed  a  mixture  of  dry  air  and  acetylene  into 
sulphuryl  chloride  without  noticing  explosion  or  com- 
bustion. On  the  contrary,  quiet  union  of  acetylene 
and  chlorine  resulted,  with  the  formation  of  tetra- 
chloride  of  acetylene.  This  seems  very  strange  if, 
according  to  Mouneyrat,  the  principal  cause  of  explo- 
sion of  acetylene  with  free  chlorine  is  to  be  referred 
to  the  presence  of  oxygen.  In  view  then  of  this 
fact,  we  should  be  led  to  conclude  that  either  free 
chlorine  is  not  present  at  ordinary  temperatures  in 
the  aluminium  and  sulphuryl  chloride  mixtures,  or 
prior  to  and  independently  of  the  presence  of  oxygen 
another  cause  must  operate  to  initiate  the  explosion 
of  free  chlorine  and  acetylene  when  brought  together. 

The  phenomenon  of  explosion  or  spontaneous  com- 
bustion was  not  found  to  occur  even  when  the 
mixture  of  aluminum  chloride  and  sulphuryl  chloride 
was  heated  while  acetylene  was  being  passed  into  the 
flask.  The  operation  was  performed  on  a  water- 
bath  so  that  the  contents  boiled  vigorously.  The 
reflux  condenser  remained  open  to  the  air,  and  no 
precautions  were  made  to  exclude  air.  Owing  to 
the  heat,  signs  of  decomposition  set  in  as  soon  as  the 
acetylene  was  passed  into  the  mixture.  The  yield 
of  tetrachloracetylene  was  poor  as  tarry  products 


were  formed.  This  was  probably  due  the  direct 
union  of  sulphuryl  chloride  with  acetylene  under 
these  circumstances  to  form  sulphonechlorides  of 
acetylene. 

CHI«ORINATTON  OF  ETHYI,ENE  WITH  SUI^PHURYI,  CHLORIDE 
IN  THE  PRESENCE  OF  ALUMINIUM  CHLORIDE. 

Ethylene,  like  acetylene,  does  not  act  on  sulphuryl 
chloride  alone,  at  ordinary  temperatures.  No  traces 
either  of  chlorides  or  sulphonechlorides  could  be  thus 
obtained.  If,  however,  some  aluminium  chloride  be 
added,  absorption  slowly  takes  place.  The  action 
can  be  accelerated  by  frequent  shaking  of  the  mixture. 

The  union  was  effected  in  a  Bulterow's  apparatus. 
The  ethylene  was  made  in  the  usual  way,  from  sul- 
phuric acid  and  alcohol.  The  gas  was  purified  by 
passing  it  through  strong  sulphuric  acid  and  caustic 
potash  solution,  and  was  collected  in  a  gasometer.  It 
was  dried  by  passing  it  through  strong  sulphuric  acid 
and  a  drying  cylinder  containing  fused  calcium  chlo- 
ride, and  then  absorbed  in  the  Butlerow's  apparatus 
containing  a  solution  of  aluminium  chloride  in  sul- 
phuryl chloride.  Very  little  rise  in  temperature  was 
noticed.  After  the  absorption  ceased,  the  contents 
were  decomposed  by  pouring  them  into  cold  water. 
An  oil  was  left  that  had  an  ethereal  odor  like  chloro- 
form mingled  with  traces  of  the  odor  of  mustard  oil. 
The  product  was  washed  with  a  dilute  solution  of 
caustic  potash,  then  with  water,  and  was  finally  dried 
over  fused  calcium  chloride.  One  half  of  the  product 
distilled  on  a  water-bath,  and  was  afterward  found  to 
boil  exactly  at  83°  C.  It  was  very  pure  and  did  not 


possess  the  odor  of  mustard  oil.  The  second  fraction 
had  the  odor  of  chloroform,  and  consisted  of  a  mix- 
ture of  higher  boiling  chlorides  and  sulphonechlorides 
with  a  very  disagreeable  odor.  Attempts  to  distill  it 
soon  ended  by  decomposition  and  charring  of  the 
contents  of  the  flask.  Acetylene  tetrachloride  was 
probably  the  principal  product  of  the  second  fraction, 
as  Mouneyrat  has  shown  that  ethylene  chloride  is 
further  chlorinated  in  the  presence  of  aluminium 
chloride  and  free  chlorine  especially  when  external 
heat  is  applied.  In  the  case  in  question  the  chlorine 
came  from  sulphuryl  chloride  present,  which  further 
reacted  with  ethylene  chloride  according  to  the 
reaction. 

CaH4+2SO2Cla  +  2AlCl8=C2HaCl4+2HCl+ 
2A1C13'S02. 

In  order,  if  possible,  to  separate  the  substance 
which  possessed  the  odor  of  mustard  oil,  and  which 
was  most  likely  a  sulphonechloride  of  ethylene,  about 
250  grams  of  sulphuryl  chloride  were  treated  in  the 
presence  of  aluminium  chloride  with  ethylene  gas. 
Aluminium  chloride  was  added  in  small  quantities 
from  time  to  time  only  as  fast  as  it  was  used  up  in  the 
reaction.  Ethylene  is  not  readily  absorbed  by  the 
mixture,  and  so  it  was  thought  best  to  aid  the  action 
by  heating  gently  on  a  water-bath.  The  operation 
was  carried  on  in  a  round  bottom  flask  fitted  with  a 
reflux  condenser.  When  the  gas  has  been  passed 
through  the  mixture  for  some  time,  the  contents  of 
the  flask  took  on  a  dark  color.  Towards  the  close  of 
the  action  aluminium  chloride  ceased  to  be  dissolved. 


The  product  was  then  distilled  on  a  water-bath,  and 
a  clear  oil  came  over  between  35°  and  45°  C.,  under 
a  pressure  of  500  mm.  This  was  mostly  pure  ethy- 
lene  chloride  mixed  with  an  excess  of  sulphuryl 
chloride.  The  latter  was  decomposed  with  water  and 
the  residue  when  washed,  dried,  and  distilled,  was 
found  to  boil  at  exactly  83°  C.  under  atmospheric 
pressure.  The  whole  liquid  came  over  to  the  last 
drop  at  the  boiling  point  of  ethylene  chloride.  The 
product  remained  pure  and  retained  its  characteristic 
pleasant  odor  for  many  months,  thus  showing  it  to  be 
umixed  with  any  impurities  whatever.  Unlike  ethy- 
lene chloride  made  by  direct  union  of  the  gases  it  did 
not  become  pink  colored  on  standing,  neither  was  a 
disagreeable  odor  noticed  even  after  half  a  year. 
The  method  seems  well  adapted  for  the  rapid  prepa- 
ration of  pure  ethylene  chloride  in  the  laboratory. 

The  residue  was  cooled  with  ice-water  and  then 
decomposed  with  very  cold  water.  The  disagreeable 
odor  was  noted  as  before.  A  dirty,  pasty  mass  was 
left,  which  seemed  to  indicate  the  presence  of  a  large 
quantity  of  tarry  products.  It  was  subjected  to  dis- 
tillation on  a  water-bath,  and  impure  ethylene  chlo- 
ride was  obtained.  The  residue  was  then  heated  on 
a  Babo  air  bath,  and  signs  of  decomposition  were 
noticed  before  the  temperature  of  150°  C.  was  ob- 
tained. Hydrochloric  acid  fumes  were  given  off  and 
carbon  separated.  After  this  initial  decomposition 
had  ceased,  a  heavy  oil  distilled  at  200°  C.  Dense 
white  fumes  were  evolved  from  it  in  presence  of  moist 
air.  It  possessed  the  odor  of  mustard  oil,  and  the 
other  characteristics  of  isethionyl  chloride  which  boils 


—  n6  — 

at  200°  C.  It  was  very  very  impure,  however,  and 
contained  empyreumatic  products.  Chlorsulphone 
chloride  of  ethylene  was  formed  according  to  the 
reaction. 

_CH2S02C1 


AMYI.ENE  AND  SULPHUR  YI,  CHLORIDE. 

Though  acetylene  and  ethlene  did  not  react  with 
sulphuryl  chloride  unless  the  action  be  accelerated  by 
means  of  aluminium  chloride,  amylene  on  the  contrary 
reacted  directly.  When  even  small  quantities  of  the 
compounds  were  brought  together,  amylene  broke 
up  the  sulphuryl  chloride  molecule  with  almost  ex- 
plosive violence.  A  few  drops  of  each  in  a  test-tube 
gave  off  much  heat  in  union  and  in  a  few  seconds 
boiled  so  strongly  as  to  dash  the  contents  out  of  the 
tube.  Chlorides  of  pentane  were  formed. 

Accordingly,  it  was  found  necessary  in  chlorinating 
the  compound  with  sulphuryl  chloride,  to  dilute  the 
amylene  by  dissolving  it  in  twice  its  weight  of  chloro- 
form, and  cooling  the  flask  with  a  freezing  mixture. 
A  reflux  condenser  was  attached  to  the  flask  contain- 
ing 50  grams  of  amylene  dissolved  in  100  grams  of 
chloroform.  About  100  grams  of  sulphuryl  chloride 
were  slowly  allowed  to  enter  the  flask  from  a  drop- 
ping funnel.  An  immediate  action  took  place.  When 
the  union  was  effected  rapidly,  the  contents  gave  off 
so  much  heat  as  to  boil  in  a  freezing  mixture,  sul- 
phur dioxide  being  evolved.  Nearly  an  hour  was 
needed  to  introduce  all  the  sulphuryl  chloride.  After 
the  action  was  completed,  the  flask  was  moderately 
warmed  and  sulphur  dioxide  driven  out.  The  con- 


tents  are  distilled  on  a  water-bath,  when  the  excess 
of  chloroform  was  separated,  mixed  with  a  small 
quantity  of  sulphuryl  chloride.  Sulphur  dioxide  gas 
remained  in  solution.  The  chlorides  of  amylene  were 
then  fractionated.  Below  the  temperature  of  130°  C. 
a  mixture  of  chloroform  and  some  amylene  chloride 
distilled.  Amylene  chloride  itself  came  over  from 
130°  C.  to  140°  C.  Trichlorpentane  was  also  formed 
and  went  over  at  higher  temperatures  together  with 
amylene  chloride.  The  higher  boiling  fractions 
possessed  the  characteristic  camphor  odor  and  taste  of 
trichlorpentane.  The  reactions  may  be  represented 
as  follows : 

C5H10+S02C12  =C5H10C12+S02. 

C5H10C12+S02C12=C5H9C13+HC1+S02. 
The  amylene  which  was  used  boiled  at  45°  C.  Both 
the  hydrocarbon  and  the  chloroform  were  previously 
dried  perfectly  with  fused  calcium  chloride.  When 
aluminium  chloride  was  added  tarry  products  were 
formed,  and  solids  resulted  having  a  rather  unpleasant 
camphor  odor,  but  the  yield  of  amylene  chloride  itself 
was  not  good.  No  sulphur  compounds  were  noticed 
when  aluminium  chloride  was  not  used.  The  higher 
fractions  underwent  partial  decomposition  in  rectifying, 
carbon  was  separated  and  hydrochloric  acid  was 
evolved. 

BEHAVIOUR  OF  ACETYLENE   TOWARDS   OTHER  CHLO- 
RIDES AND  CHLORINATING  AGENTS. 
ACETYLENE  AND  DlSULPHUR  BICHLORIDE. 

When   acetylene   was  passed   into    disulphur    di- 
chloride  kept  boiling  in  a  flask  with  a  reflux  con- 


—  n8  — 

denser,  the  gas  was  very  slowly  absorbed.  The  action, 
however,  was  very  imperfect.  When  the  product 
was  decomposed  with  water  an  organic  oil  is  left  in 
small  quantity.  It  was  very  impure,  mixed  with 
sulphur  and  possessed  a  disagreeable  alliaceous  odor. 
The  precipitate  of  free  sulphur  retained  this  odor  for 
a  long  time  after  decomposition  with  water.  When 
aluminium  chloride  was  added  to  the  disulphur  di- 
chloride  into  which  acetylene  had  been  passed  for 
several  days,  an  immediate  and  strong  reaction  took 
place  accompanied  by  a  change  of  color  of  the  contents 
of  the  flask  from  clear  yellowish  red  to  opaque  brown. 
When  acetylene  was  passed  into  disulphur  dichloride 
in  the  presence  of  aluminium  chloride,  the  gas  was 
completely  absorbed  with  the  evolution  of  so  much 
heat  that  the  flask  had  to  be  cooled  with  water,  or  the 
flow  of  gas  temporarily  diminished  to  prevent  total 
decomposition  of  the  products  formed.  Towards  the 
end  of  the  reaction  the  mixture  of  disulphur  dichlo- 
ride and  aluminium  chloride  tended  to  solidify  on 
exposure  to  the  air.  Fractional  distillation,  even 
under  diminished  pressure,  failed  to  separate  the  com- 
pounds formed.  Decomposition  took  place  before  a 
temperature  of  140°  C.  was  reached.  The  first  frac- 
tion of  the  distillate  was  of  a  light  straw  color,  and 
possessed  the  characteristics  of  thiocarbonyl  chloride. 
It  fumed  strongly  in  the  air.  At  a  temperature  of 
74°  C.  and  300  mm.  pressure  it  began  to  distill.  The 
color  of  the  distillate  became  a  darker  red  between 
121°  C.  and  141°  C.  under  350  mm.  pressure.  At 
1 60°  C.  a  beautiful  violet  colored  product  distilled, 
and  almost  simultaneously  decomposition  set  in  with 


Or  THE" 

UNIVERSITY 

or 


the  separation  of  carbon,  sulphur,  and  hydrocnToric 
acid.  The  carbon  separated  in  hard  compact  form 
like  coke.  One  of  the  products  of  decomposition  was 
a  greasy  black  product  which  separated  with  the 
violet  oil  above  1  60°  C.  The  oil  could  not  be  redistilled 
under  atmospheric  pressure  without  undergoing 
decomposition.  On  decomposing  the  product  of  re- 
action a  very  small  quantity  of  impure  acetylene 
tetrachloride  was  obtained.  When  the  product  of 
the  reaction  of  acetylene  with  disulphur  dichloride  in 
presence  of  aluminium  chloride  was  decomposed 
before  distillation  by  pouring  it  into  well  cooled 
water,  acetylene  tetrachloride  in  very  impure  con- 
dition mixed  with  alumina  and  sulphur,  was  obtained. 

Guthrie1  has  shown  that  ethylene  forms  additional 
compounds  with  disulphur  dichloride,  when  the  gas 
was  passed  into  the  heated  compound.  Substances 
of  the  formula,  C2H4C12'S2C12,  and  (  C2H4)2'S2C12, 
were  obtained. 

Attempts  were  made  to  obtain  the  similar  acety- 
lene compounds  that  might  be  formed  by  the  action 
of  dry  acetylene  upon  aluminium  chloride  and  disul- 
phur and  dichloride.  The  products  of  the  reaction  were 
decomposed  with  water,  and  a  solid  mass  containing 
sulphur  and  tetrachlorethane  was  extracted  with 
several  liters  of  ether,  in  which  the  compound  is  some- 
what soluble.  After  evaporating  the  ether,  an  oily 
residue  was  left  that  crystallized  in  radiating  needles, 
slightly  tinged  with  a  purple  violet.  It  was  mixed 

ijour.  Chem.  Soc.  XIII.,  35,  129,  XIV.,  128.  Ann.  113, 
266,  and  1  1  6,  234. 


—  120  

with  tetrachlorethane  and  disulphur  dichloride.  The 
crystals  could  not  be  purified  or  separated  from 
the  other  products.  The  extract  with  carbon  disul- 
phide  instead  of  ether,  underwent  general  decompo- 
sition, carbon,  sulphur  and  hydrochloric  acid  being 
the  final  products. 

ACETYLENE  AND  SULPHUR  DICHLORIDE,  (SCla). 

Acetylene  was  absorbed  more  readily  by  sulphur 
dichloride  than  by  disulphur  dichloride,  but  as  the 
former  gave  off  free  chlorine,  it  was  necessary  to  cool 
the  flask  with  ice-water  and  carefully  to  regulate  the 
stream  of  acetylene,  in  order  to  prevent  spontaneous 
combustion  of  the  escaping  gases.  By  allowing  the 
acetylene  to  enter  the  compound  through  a  capillary 
tube  all  danger  of  explosion  was  obviated.  The  escap- 
ing gases  were  at  times  spontaneously  inflamed  at  the 
beginning  of  the  operation.  This  occurred  especially 
when  they  were  allowed  to  bubble  through  water,  the 
gas  bubbles  then  exploding  on  contact  with  the  air. 
There  was  reason  to  believe  that  a  great  part  of  the 
acetylene  absorbed  was  not  chemically  acted  upon 
but  only  held  in  solution.  When  aluminium  chloride 
was  added  to  the  contents  of  the  flask  after  passing  in 
acetylene  some  hours,  a  sudden  and  violent  reaction 
takes  place,  accompanied  with  combustion  of  the 
evolved  gases,  and  separation  of  carbon.  The  residue 
took  on  a  dark  brown  color  and  became  very  hot.  Hydro- 
chloric acid  was  slowly  evolved.  The  products  of  the 
reaction  after  adding  aluminium  chloride  and  continu- 
ing the  absorption  of  acetylene  were  apparently  the 
same  as  in  the  case  of  disulphur  dichloride.  Frac- 


—   121  — 

tional  distillation  even  under  diminished  pressure  did 
not  give  pure  products.  More  tetrachloracetylene 
was  obtained  than  in  the  previous  experiment.  The 
study  of  the  action  of  acetylene  upon  the  chlorides  of 
sulphur  will  be  continued. 

ACETYLENE  AND  VARIOUS  OTHER  CHLORIDES. 

(THIONYL  CHLORIDE,  SOCk). 

Acetylene  did  not  react  with  thionyl  chloride  even 
in  the  presence  of  aluminium  chloride  at  oridinary 
temperature.  When  the  mixture  of  chlorides  was 
heated  while  acetylene  was  passed  into  the  com- 
pounds, tarry  products  were  obtained  possessing  a 
very  disagreeable  odor  like  that  of  the  sulphone 
chlorides  of  the  aromatic  series.  Small  quantities  of 
the  products  of  reaction  were  obtained  as  a  dark 
brown  gummy  mass,  on  decomposing  the  contents  of 
the  flask  with  water. 

(STANNIC    CHLORIDE,    SUCl.4) 

Pure  anhydrous  redistilled  stannic  chloride,  free 
from  chlorine,  did  not  give  up  part  of  its  chlorine  to 
acetylene  even  in  the  presence  of  aluminium  chloride. 
When  the  heat  was  applied,  acetylene  was  decom- 
posed in  part,  leaving  hard  particles  of  carbon  floating 
in  the  liquid,  but  no  chloracetylene  was  obtained. 
The  stannic  chloride  boiled  at  114°  C.  and  was  pure 
and  perfectly  anhydrous. 

PLUMBIC  CHLORIDE,    (PDCfc),  AND  PLUMBIC  AMMONIUM  CHLORIDE, 
(PbCl4,2NH4Cl). 

When  acetylene  was  passed  into  the  solution  of 
plumbic  chloride  in  strong  hydrochloric  acid,  explo- 
sions took  place  by  reason  of  the  free  chlorine 


122  

constantly  evolved  from  the  compound.  Crystalline 
plumbic  ammonium  chloride  has  been  found  to  give 
up  chlorine  readily  to  aromatic  hydrocarbons.  Acety- 
lene, however,  gave  no  chlorine  reaction  products 
even  in  presence  of  aluminium  chloride,  nor  when 
both  chlorides  were  dissolved  in  another  liquid  chlo- 
ride, such  as  phosphorus  trichloride.  When  calcium 
carbide  is  heated  with  plumbic  ammonium  chloride, 
a  violent  reaction  takes  place,  but  no  acetylene 
chloride  was  obtained.  The  products  seemed  to  be 
similar  to  those  made  by  Salvador!1  by  the  action  of 
ammonium  chloride  on  calcium  carbide.  As  no 
acetylene  chloride  was  obtained,  the  action  of  acety- 
lene with  plumbic  chloride  was  not  further  investi- 
gated. 

CARBONYL  CHLORIDE  (COCls),  CYANOGEN  CHLORIDE  (CUCl),  NITROSYL 
CHLORIDE  (NOCl). 

None  of  these  gases  showed  any  reaction  whatever 
with  acetylene.  Carbonyl  chloride  and  nitrosyl  chlo- 
ride were  also  passed  with  acetylene  over  aluminium 
chloride  without  any  signs  of  union.  The  latter  in 
the  nascent  condition  evolved  from  nitrosulphonic 
acid,  sodium  chloride,  and  sulphuric  acid  failed  to 
give  any  organic  compound  when  acetylene  was 
passed  into  the  mixture. 

ANTIMONY  TRICHLORIDE,  (sbcls),  AND  PHOSPHORUS  PENTACHLORIDE, 
(PCl6), 

When  antimony  trichloride  and  aluminium  chloride 
were  heated  together  while  acetylene  was  passed  over 
the  compounds,  only  traces  of  tarry  products  were 

i  Gaz.  XXXII.,  II.,  496,  ( 1902). 


-  123- 

obtained  possessing  very  disagreeable  odors.  Phos- 
phorus pentachloride  did  not  give  up  part  of  its 
chlorine  to  acetylene  even  in  the  presence  of  alumi- 
nium chloride.  When  a  solution  of  phosphorus 
pentachloride  and  aluminium  chloride  in  phosphorus 
trichloride  was  heated  below  the  dissociating  point  of 
phosphorus  pentachloride  while  acetylene  was  passed 
into  the  boiling  mixture,  no  better  results  were  ob- 
tained. Only  traces  of  ill-smelling  organic  compounds 
were  found  on  decomposing  the  product  of  reaction. 
When  phosphorus  pentachloride  was  further  heated,  it 
dissociated.  Explosions  took  place  whenever  acety- 
lene was  passed  over  it  at  higher  temperatures. 

CHROMYL  CHLORIDE,  (CrO2Cl2). 

As  this  compound  gives  off  free  chlorine  very 
readily,  and  is  likewise  a  powerful  oxydizing  agent, 
violent  explosions  would  be  expected  when  acetylene 
is  passed  into  chromyl  chloride.  In  fact,  every 
attempt  to  introduce  acetylene  into  the  flask  contain- 
ing this  substance  ended  in  an  explosion  or  spon- 
taneous combustion  of  the  gas  and  separation  of 
carbon. 

ARSENIC  TRICHLORIDE,    (ASCla). 

Pure  arsenic  trichloride  free  from  oxide  did  not 
show  any  reaction  with  perfectly  dry  acetylene. 
When  aluminium  chloride  was  added  the  absorption 
of  the  gas  was  effected  with  the  evolution  of  consider- 
able heat.  The  contents  of  the  flask  turned  black. 
When  decomposed  by  pouring  the  substance  into  cold 
water,  a  black  gummy  mass  separated  out,  and  on 
standing  for  some  time  crystals  appeared  in  the  aqueous 
solution.  The  tarry  substance  possessed  a  most 


-  I24  — 

nauseating  and  penetrating  odor,  and  was  extremely 
poisonous.  Inhalation  of  the  fumes,  even  in  small 
quantity  caused  nervous  depression.  No  chlorine 
derivatives  of  acetylene  were  noted.  Owing  to  the 
poisonous  nature  of  the  compounds  formed,  their 
thorough  investigation  was  postponed. 

ACETYLENE  AND  DRY  IODINE  TRICHLORIDE,    (ids). 

The  action  of  acetylene  upon  iodine  trichloride  in 
solution  of  strong  hydrochloric  acid  was  studied  by 
Plimpton  and  Sabanejef.  Monochlormoniodacetylene 
was  formed.  Chloriodacetylenes  were  formed  with 
more  than  one  atom  of  chlorine  in  the  molecule  and 
could  not  be  distilled,  as  they  decomposed  with  the 
separation  of  iodine  at  1 20°  C. 

To  obtain  the  crystals  of  iodine  trichloride,  iodine 
was  heated  in  a  retort  while  a  stream  of  dry  chlorine 
was  passed  into  the  vapor.  Connected  with  the  retort 
was  a  flask  with  two  ground  glass  openings.  The 
neck  of  the  retort  was  fitted  into  one  of  these  so  that 
it  was  not  necessary  to  use  rubber  or  cork  connec- 
tions. The  trichloride  was  sublimed  into  the  fiask 
in  a  stream  of  dry  chlorine,  care  being  taken  that  no 
iodine  monochloride  was  allowed  to  pass  over.  When 
all  the  trichloride  was  sublimed  into  the  receiver 
chlorine  was  passed  for  some  time  to  get  rid  of  the 
traces  of  monochloride  of  iodine.  The  well-stopped 
receiver  containing  the  iodine  trichloride  in  an  atmo- 
sphere of  chlorine  was  then  put  aside  for  twenty-four 
hours. 

Acetylene  was  then  passed  in  through  one  of  the 
openings  by  means  of  a  capillary  tube.  The  gas  was 
absorbed  as  fast  as  it  entered,  and  more  acetylene  was 


-  125  — 

drawn  in  by  reason  of  the  vacuum  created  by  absorp- 
tion, as  the  other  opening  of  the  flask  was  kept 
closed  with  a  cork.  The  heat  evolved  in  the  reaction 
was  considerable,  and  the  flask  was  cooled  by  a  stream 
of  cold  water.  The  first  stage  of  reaction  seemed  to 
be  that  of  chlorination,  as  iodine  monochloride  was 
separated  as  soon  as  the  acetylene  entered.  No  ex- 
plosion occurred.  As  soon  as  all  the  iodine  trichlo- 
ride had  disappeared,  the  operation  was  immediately 
interrupted,  and  the  free  iodine  and  iodine  mono- 
chloride  removed  from  the  oil  which  was  then  clear 
and  odorless.  The  dried  product  was  distilled. 
Very  little  distillate  was  obtained  below  126°  C. 
The  temperature  then  rose  to  146°  C.,  when  much 
iodine  separated  and  the  greater  part  of  the  oil  dis- 
tilled over.  Monochlormoniodacetylene  boiled  be- 
tween 1  1  6°  and  119°  C.  And  therefore,  little  if  any 
was  present.  Acetylene  tetrachloride  was  the  principal 
or  at  least  the  first  product  of  reaction  between 
acetylene  and  dry  iodine  trichloride.  Chloriodacety- 
lene  was  the  result  of  a  secondary  reaction.  The  fact 
that  iodine  monochloride  comes  out  as  soon  as 
acetylene  reacted  with  the  solid  trichloride  of  iodine, 
sufficiently  demonstrated  this.  The  trichloride  of 
iodine  then,  acted  as  a  chlorinating  agent,  and  when 
the  operation  was  interrupted  after  all  the  trichloride 
of  iodine  was  used  up,  very  little  if  any  acetylene 
iodochloride,  C2H2C1I,  was  obtained.  The  reaction 
may  be  represented  as  follows  : 


la  =  CaHaCl4+2lCl. 

When  an  excess  of  acetylene  is  present,  the  iodine 


—  126  — 

monochloride  reacted  further  with  the  hydrocarbon  to 
form  monochlormoniodacteylene  according  to  the 
reaction  : 

C2H2-fICl  =  C2H2ICl. 

Other  reactions  forming  compounds  of  acetylene 
with  chlorine  and  iodine  containing  more  than  one 
atom  of  chlorine  took  place  independently  of  those 
referred  to.  It  is  also  noteworthy  that  a  compound  as 
easily  dissociated  as  iodine  trichloride  in  the  dry 
state  does  not  explode  with  acetylene. 

ACETYLENE  AND  "  AQUA  REGIA." 

The  chlorinating  action  of  ' '  aqua  regia ' '  is  said  to 
be  due  to  the  evolution  of  chlorine  in  the  nascent 
state  when  the  mixture  is  warmed,  and  this  effect  is 
produced  according  to  the  reaction  : 

3HC1+HNO3=2H20+NOC1+C12. 

When  acetylene  was  passed  into  * '  aqua  regia ' '  at 
ordinary  temperature  or  even  at  the  boiling  point  of 
the  solution,  no  explosion  or  spontaneous  combustion 
was  ever  observed,  though  air  was  present  during 
the  operation.  The  gas  was  passed  into  the  acids 
both  in  a  slow  and  rapid  stream.  Evident  signs  of 
reaction  were  noted  by  the  formation  of  an  oil  in 
small  quantity.  Even  the  small  quantity  that  was 
formed  seemed  to  be  decomposed  by  the  continued 
action  of  the  "aqua  regia."  The  presence  of  hexa- 
chlorethane  was  observed.  Small  acicular  crystals 
of  this  compound  floated  in  the  acids,  but  the  yield 
of  tetrachlorethane  and  hexachlorethane  was  very 
small.  The  latter  compound  resulted  from  the  con- 


-  127- 

tinued  action  of  nascent  chlorine  on  the  tetrachloride 
of  acetylene  when  the  latter  was  not  immediately 
removed  from  the  scene  of  action  by  distillation. 
The  reaction  may  be  expressed  as  follows  : 

3HCH-HN03=H2O+NOC1+C12, 

2C12+C2H2=C2H2C14, 
CaHaCl4+2Cla  =C2C1«+2HC1. 

When  dry  hydrochloric  acid  gas  were  passed  into 
fuming  nitric  acid,  no  chlorine  derivatives  of  acety- 
lene were  obtained.  Nitro-compounds  of  acetylene 
were  obtained  when  the  acid  was  diluted  with  water.1 

When  very  strong  hydrochloric  acid  (Sp.  gr.  1.20) 
was  boiled  with  strong  nitric  acid  while  a  rapid  stream 
of  acetylene  was  passed  into  the  flask  connected  with 
a  L,iebig  condenser,  tetrachloracetylene  was  obtained 
in  greater  quantity.  It  contained,  however,  as  an 
impurity  a  nitrogen  compound  with  a  penetrating 
odor  which  caused  a  painful  flow  of  tears.  Its  solu- 
tion in  the  oil  gave  to  the  latter  a  pale  green  color. 

So  strong  a  reagent  as  '  *  aqua  regia ' '  did  not  cause 
any  explosion  with  acetylene  though  free  chlorine  was 
present.  Moreover,  air  was  present  in  all  these 
experiments  and  not  the  slightest  trace  of  carbon  was 
separated.  When  nascent  acetylene  was  used,  reac- 
tions with  "  aqua  regia"  gave  the  same  results,  tetra- 
chlorethane  and  hexachlorethane  being  obtained. 
This  was  accomplished  by  throwing  pieces  of  calcium 
carbide  into  the  acid.  Calcium  carbide  decomposed 

lGaz.  XXXII.,  I.,  202,  (1902).  Gaz.  XXXI.,  II.,  465, 
(1901). 


—  128  — 

rather  slowly  in  the  mixture,  and  hexachlorethane 
was  the  principal  product.  In  this  case  no  spontaneous 
combustion  or  explosion  resulted,  though  very  much 
heat  was  evolved  from  the  decomposition  of  the  cal- 
cium carbide. 

ACETYLENE  AND  ANTIMONY  PENTACH^ORIDE,  (sbc!5 ) . 

The  method  of  preparing  tetrachlorethane  by  means 
of  antimony  pentachloride  and  acetylene,  discovered 
by  Berthelot  and  Jungfleisch1  in  1872,  might  be  con- 
sidered a  more  or  less  convenient  way  of  preparing 
that  compound.  When  acetylene  was  passed  into 
antimony  pentachloride,  the  gas  was  more  or  less 
readily  absorbed,  varying  with  certain  conditions  not 
as  yet  well  determined.  On  cooling  the  contents  of 
the  flask  crystals  of  the  compound,  SbCl3'C2H2Cl2, 
separated  out  When  these  were  heated,  a  mixture 
of  tetrachloracetylene  was  supposed  to  be  formed 
according  to  the  reactions  : 

C2H2+SbCl5:=SbCl3-C2H2Cl2, 

SbCl3'C2H2Cl2  =C2H2Cl2+SbCl3, 

SbCl3'C2H2Cl2+SbCl5=C2H2Cl4+2SbCl3. 

If  the  compound  of  acetylene  and  antimony  penta- 
chloride be  heated  with  an  excess  of  antimony  penta- 
chloride, tetrachlorethane  alone  was  obtained. 

Sabanejef  ,2  eleven  years  later,  repeated  this  work 
and  obtained  very  unsatisfactory  results^  He  com- 
plained that  the  absorption  took  place  slowly  and 


1  Ann.  Chim.  Phys.  26,  473,  (1872).     Carb.   D'Hyd.  I.,  311. 

2  Ann.  216,  261. 


—  129  — 

with  difficulty,  that  very  little  heat  was  evolved,  and 
that  explosions  often  occurred  on  shaking.  He  did 
not  succeed  in  obtaining  the  crystalline  compound 
mentioned  by  Berthelot  although  he  had  passed  the 
acetylene  into  the  antimony  pentachloride  for  a  con- 
siderable time. 

I  have  repeated  the  experiments  of  Berthelot  and 
Jungfleisch  and  have  come  to  the  same  conclusions. 
Generally,  antimony  pentachloride  absorbed  acety- 
lene quite  readily,  but  at  times,  for  some  unknown 
reason,  the  action  at  the  beginning  of  the  experiment 
was  remarkably  slow.  I  have  not  found  any  good 
cause  for  the  fact.  If,  however,  the  contents  of  the 
flask  be  allowed  to  stand  for  a  day  after  passing 
the  gas  the  subsequent  action  is  quite  energetic. 
This  fact  would  seem  to  show  that  acetylene  is  dis- 
solved only  in  part,  that  it  is  not  chemically  combined, 
but  that  combination  results  on  standing  for  some 
time.  On  one  occasion  acetylene  gas  was  passed  for 
a  whole  day  into  the  antimony  pentachloride  with 
very  little  result.  The  next  day  the  gas  was  again 
allowed  to  pass  into  the  compound,  and  the  action 
was  so  energetic  that  it  was  deemed  advisable  to  cool 
the  flask  with  water  during  absorption.  This  heat 
was  evolved  within  fifteen  minutes  from  the  time 
that  the  gas  was  allowed  to  enter  the  apparatus. 

The  method  of  Berthelot  and  Jungfleisch  for  the 
preparation  of  tetrachlorethane,  consisted  in  the  dis- 
tillation of  the  compound  of  antimony  pentachloride 
and  acetylene,  SbCl3'C2H2Cl2,  with  an  excess  of 
antimony  pentachloride.  Two  molecules  of  antimony 
pentachloride  gave  up  four  atoms  of  chlorine  with 


-  130  ~ 

the  formation  of  tetrachlorethane.  This  process 
involved  the  use  of  much  antimony  compound  in 
order  to  prepare  a  small  quantity  of  acetylene  tetra- 
chloride.  If,  instead  of  distilling  the  compound, 
SbCl3'C2H2Cl2,  with  one  molecule  of  antimony 
pentachloride,  dry  chlorine  gas  was  passed  into  the 
contents  of  the  flask  after  previously  driving  out  the 
gaseous  or  undissolved  acetylene  by  means  of  a  blast 
of  dry  air,  the  same  result  could  be  effected.  No 
explosion  took  place  and  the  chlorine  gas  was  absorbed 
with  great  avidity,  and  the  evolution  of  so  much 
heat  that  the  flask  had  to  be  cooled.  The  compound, 
SbCl3'C2H2Cl2,  took  up  two  molecules  of  chlorine 
gas,  forming  tetrachloracetylene  and  leaving  anti- 
mony pentachloride  according  to  the  reaction  : 

SbCl3-C2H2Cl2+2Cl2=C2H2Cl4+SbCl5. 

Now  as  antimony  pentachloride  was  again  present  in 
the  solution,  acetylene  could  be  passed  into  the  flask 
after  driving  out  the  excess  of  uncombined  chlorine 
by '  means  of  dry  air  or  some  other  inert  gas.  The 
process  of  alternately  passing  the  two  gases  into  the 
compound  could  be  carried  on  indefinitely  Instead 
of  using  the  antimony  pentachloride  as  a  reagent,  it 
was  used  rather  in  the  function  of  "carrier,"  the 
same  amount  of  substance  being  used  indefinitely,  or 
even  for  several  separate  experiments.  It  could  be 
obtained  unchanged  at  the  end  of  the  operation  by 
distilling  off  the  tetrachlorethane. 

The  absorption  of  chlorine  was  so  rapid  and  per- 
fect, that  if  the  exit-tube  be  closed,  the  air  was  drawn 
through  the  safety  tube  in  the  chlorine  generating 


flask,  by  the  diminished  pressure  due  to  the  rapid 
absorption  of  chlorine.  Moreover,  when  the  acety- 
lene had  been  passed  alternately  several  times,  its 
rate  of  absorption  was  also  improved,  and  great  heat 
was  given  off  to  the  reaction.  No  explosion  occurred 
when  the  excess  of  one  gas  was  driven  out  before 
passing  the  other  into  the  apparatus.  No  more  than 
five  minutes  was  necessary  to  effect  this.  When  the 
the  absorption  of  either  gas  was  not  allowed  to  pro- 
ceed to  complete  saturation,  so  that  no  uncombined 
gas  was  present  in  solution,  it  was  not  even  necessary 
to  resort  to  the  precaution  of  using  a  blast  of  air  to 
drive  out  the  gas  last  absorbed.  This  point  of 
saturation  was  easily  determined  by  the  fact  that 
heat  ceased  to  be  evolved  when  absorption  no  longer 
took  place. 

In  one  experiment  twenty-five  grams  of  antimony 
pentachloride  were  treated  as  above  described.  A 
flask  with  a  reflux  condenser  was  used.  The  latter, 
however,  was  not  strictly  necessary  as  the  products 
of  reaction  are  not  very  volatile.  A  tube  bent  at 
right  angles  was  connected  with  two  T- tubes  and 
stop-cocks  to  admit  the  gas  alternately,  likewise  one 
connection  with  air  from  blast.  The  air  was  dried 
by  passing  through  a  cylinder  containing  fused  cal- 
cium chloride.  The  acetylene  was  dried  by  passing 
through  a  wash -bottle  containing  strong  sulphuric  acid 
and  thence  through  a  drying  cylinder  containing  cal- 
cium carbide.  The  tube  bent  at  right  angles  through 
which  the  gases  were  introduced  into  the  absorption 
flask,  was  drawn  out  of  the  liquid  before  passing  each 
gas,  so  that  in  case  the  previous  gas  were  not  perfectly 


-  132  - 

eliminated  by  the  air-blast,  no  loss  of  substance  would 
be  sustained  by  the  slight  explosion  that  might  occur, 
forcing  the  contents  back  by  the  concussion.  Explo- 
sions only  occurred  when  either  gas  was  passed  in 
longer  than  necessary,  that  is,  after  it  ceased  to  be 
absorbed.  Dissolved  uncombined  gases  were  with 
difficulty  removed.  Chlorine  could  however,  be 
removed  by  adding  a  small  quantity  of  antimony 
trichloride,  and  acetylene  with  antimony  pentachlo- 
ride,  if  one  could  not  wait  until  the  gases  were  driven 
out  with  the  air-blast.  Only  when  changing  the  gases, 
and  then  only  when  not  perfectly  eliminated  did  the 
introduction  of  one  or  the  other,  cause  slight 
explosion. 

In  the  experiment  in  question,  after  passing  the 
acetylene  and  chlorine  alternately  several  times,  the 
net  increase  in  weight  amounted  to  forty-six  grams. 
The  product  was  distilled,  and  pure  tetrachlore thane 
obtained.  No  trace  of  dichloracetylene,  C2H2C12, 
was  found.  No  impurities  were  present  after  the 
distillate  had  been  washed  with  strong  hydrochloric 
acid  and  water.  The  product  was  washed  with 
hydrochloric  acid  in  order  to  remove  a  small  quantity 
of  antimony  pentachloride  that  came  over  in  the 
distillation.  The  oil  was  dried  over  fused  calcium 
chloride  and  possessed  the  odor  of  chloroform.  It 
had  the  correct  boiling  point  of  tetrachlore  thane. 

Another  experiment  was  performed  with  two 
hundred  grams  of  antimony  pentachloride.  The 
operation  was  continued  until  a  net  increase  of  840 
grams  was  obtained  from  the  initial  200  grams  of 
antimony  pentachloride.  It  was  not  deemed  advis- 


—  133  — 

able  to  allow  the  operation  to  go  so  far,  as  it  became 
more  difficult  to  obtain  good  action  when  the  anti- 
mony pentachloride  was  diluted  with  four  times  its 
weight  of  tetrachlorethane.  It  was  also  more  difficult 
to  drive  out  the  acetylene  gas  which  tended  to 
dissolve  in  great  quantity  in  the  tetrachlorethane 
without  entering  into  chemical  combination.  The 
alternating  action,  however,  seemed  to  go  on 
indefinitely. 

According  to  the  method  of  preparing  tetrachlor- 
ethane proposed  by  Berthelot  and  Jungfleisch,  explo- 
sions were  not  altogether  eliminated.  I  have  not  had 
explosions  except  when  the  gases  were  changed,  and 
then  very  rarely.  When  one  gas  was  carefully  drawn 
out  before  introducing  the  other,  no  explosion  ever 
took  place.  (  The  perfect  elimination  of  gas  with  a 
blast  of  air  became  difficult  only  when  the  increase 
of  weight  was  great,  owing  to  the  state  of  dilution  of 
the  antimony  pentachloride.)  When  the  product 
was  finally  to  be  distilled,  chlorine  was  passed  into 
the  solution  for  the  last  time.  Explosions  were  thus 
avoided  which  are  due  to  the  separation  of  free 
acetylene  in  the  presence  of  free  chlorine. 

In  the  distillation  some  antimony  pentachloride 
passed  over  with  the  tetrachlorethane.  This  was 
removed  with  strong  hydrochloric  acid.  Nitric  acid 
did  not  insure  so  pure  a  product.  The  oil  was  next 
washed  with  water  to  free  it  from  hydrochloric  acid. 
It  was  then  dried  with  fused  calcium  chloride  and 
redistilled.  The  distillate  possessed  a  constant  boil- 
ing point  to  the  last  few  drops  within  the  frac- 
tion of  a  degree  and  was  clear  colorless 


-134- 

oil  with  pure  odor.  No  traces  of  acid  fumes  or 
unpleasant  odors  were  noticed  when  the  products  had 
been  sufficiently  dried.  Acetylene  tetrachloride  could 
thus  be  formed  in  any  desirable  quantity.  By  using 
larger  quantities  of  antimony  pentachloride  at  the 
start,  even  a  more  perfect  action  could  be  obtained, 
as  the  heat  of  the  mass-reation  greatly  promotes 
absorption.  In  fact  the  two  gases  could  be  passed 
simultaneously  into  a  suitable  vessel  provided  they 
did  not  come  in  contact  in  the  gaseous  state. 

Instead  of  distilling  off  the  tetrachlorethane,  the 
contents  of  the  flask  may  be  decomposed  in  water. 
A  white  precipitate  is  thrown  down,  which  is  prob- 
ably a  compound  of  acetylene  chloride  with  antimony 
chloride  or  oxy chloride,  or  the  crystals  of  the  com- 
pound, SbCl3'C2H2Cl2,  insoluble  in  water.  These 
are  treated  with  strong  hydrochloric  acid  to  remove 
the  antimony  when  the  oil  reappears.  After  washing 
several  times  with  hydrochloric  acid,  and  shaking 
the  oil  well  in  a  separating  funnel  with  hydrochloric 
acid,  the  tetrachlorethane  is  washed  with  water, 
dried,  and  distilled. 

Berthelot  and  Jungfleisch  seemed  to  have  been  of 
the  opinion  that  the  product  of  the  reaction  of  acety- 
lene upon  antimony  pentachloride  was  decomposed 
by  water.1  The  product  of  the  reaction  of  acetylene 
upon  antimony  pentachloride  was  not  destroyed  by 
water.  As  soon  as  it  was  poured  into  water,  a  heavy 
precipitate  was  thrown  down  that  is  not  the  oxychlo- 


1  Ann.    Chim.  Phys.   4,    XXVI.,   (1872).— Carb.  D'Hyd.  I., 
312. 


—  135  — 

ride  of  antimony,  but  a  compound  of  acetylene 
tetrachloride  and  antimony  chloride,  or  oxychloride. 
As  I  have  already  stated,  tetrachlorethane  can  be 
obtained  from  it  by  treating  it  with  strong  acids. 
Even  when  the  product  obtained  by  the  continued 
action  of  chlorine  and  acetylene  upon  antimony 
pentachloride  was  decomposed,  no  oil  was  separated 
on  pouring  into  water,  but  a  heavy  precipitate  came 
out.  Whether  this  be  the  compound,  SbCVC2H2Cl», 
referred  to  by  the  authors,  I  have  not  as  yet  been 
able  to  ascertain  with  absolute  certainty. 

The  precipitate  could  be  dried  in  a  dessicator, 
and  when  subsequently  treated  with  acids  gave 
back  the  oil.  Moreover,  the  precipitate  dissolved 
in  ether,  alcohol,  or  a  mixture  of  ether  and 
alcohol,  becoming  a  clear  solution  with  a  gray 
fluorescence.  Antimony  oxychloride  will  not  dis- 
solve in  these  solvents.  The  ethereal  .solution  of  the 
compound  was  evaporated  to  a  small  volume  and 
crystals  reappeared.  When  chlorine  was  passed  over 
them,  they  appeared  to  absorb  it  with  the  evolution 
of  heat,  so  that  the  process  of  chlorination  could  be 
continued  with  the  product  supposed  by  Berthelot  to 
be  decomposed  in  water.  This  fact  let  to  the  opinion 
that  the  precipitate  formed  when  the  product  of 
reaction  of  acetylene  upon  antimony  pentachloride 
was  poured  into  water,  was  not  a  decomposition 
product,  but  a  definite  compound  of  acetylene  with 
antimony  chloride  in  an  amorphous  state.  It  was  the 
undecomposed  product  of  union  between  acetylene 
and  antimony  pentachloride  from  which  tetrachlor- 
ethane was  easily  recovered  with  strong  acids.  In  fact 


OF  THE 

UNIVERSITY 


-136  — 

the  compound  was  simply  precipitated,  not  decom- 
posed by  water.  When  attempts  were  made  to  dry 
it  for  analysis,  it  continued  to  give  off  vapors  of 
tetrachloracetylene  and  could  not  be  dried  to  constant 
weight. 

A  simple  method  of  preparing  any  desirable 
quantity,  has  been  developed  in  this  laboratory. 
Dry  acetylene  is  passed  into  antimony  pentachloride 
contained  in  a  flask  with  a  two-holed  stopper.  The 
gas  is  brought  into  the  flask  through  a  tube  bent  at 
right  angles  and  dipping  below  the  liquid.  The 
excess  of  gas  escaped  by  another  tube.  No  reflux 
condenser  is  necessary.  When  the  antimony  penta- 
chloride is  nearly  saturated  with  acetylene,  the  excess 
of  free  gas  is  either  blown  out  with  dry  air,  or  in 
drrwn  through  by  aspiration.  Chlorine  is  then 
passed  into  the  flask,  until  the  heat  of  reaction  ceases 
when  acetylene  is  again  introduced  after  removing 
any  free  chloride  gas  present.  This  process  is  con- 
tinued until  the  net  increase  in  weight  amounts  to 
three  times  the  weight  of  antimony  pentachloride 
used  at  the  beginning  of  the  experiment.  The  pro- 
duct is  distilled,  the  distillate  washed  with  strong 
hydrochloric  acid  to  remove  antimony  compounds 
from  the  oil,  then  washed  with  water  to  remove  the 
acid.  It  is  then  dried  with  fused  calcium  chloride  or 
sodium  sulphate,  and  redistilled,  when  pure  tetra- 
chlorethane  is  obtained. 

According  to  the  method  of  preparing  tetrachlor- 
ethane  proposed  by  Berthelot  and  Jungfleisch,  only 
eight  parts  of  acetylene  can  be  absorbed  by  every 
hundred  parts  of  antimony  pentachloride  by  weight 


—  137  — 

when  the  operation  must  be  interrupted.  Accordingly 
in  the  experiment  described,  twenty  grams  of  anti- 
mony pentachloride  would  give  an  increase  of  only 
two  grams,  yielding  seven  grams  of  tetrachlorethane. 
I  obtained  forty-one  grams  increase  after  passing  the 
two  gases  alternately  several  times,  and  over  fifty 
grams  of  pure  tetrachlorethane  resulted.  Likewise, 
though  according  to  Berthelot's  method,  200  grams 
of  antimony  pentachloride  should  give  only  1 8  grams 
increase  in  weight,  with  the  subsequent  yield  of  fifty 
four  grains  of  tetrachloracetylene,  I  have  obtained  a 
net  increase  of  eight  hundred  and  forty  grams  which 
corresponds  nearly  to  a  kilogram  of  tetrachloracety- 
lene, before  the  operation  was  discontinued. 


-138- 


RE  ACTION  OF  ACETYLENE  WITH  ACIDIFIED 
MERCURIC  FLUORIDE 

Acetylene  forms  two  series  of  compounds  with  salts 
of  mercury.  Carbides  are  combinations  of  carbon 
with  a  metal,  and  mercury,  like  some  of  the  other 
heavy  metals  gives  a  carbide  when  alkaline  solutions 
of  its  salts  are  treated  with  acetylene.  The  carbides 
are  generally  explosive  and  on  treatment  with  acids 
give  off  acetylene.  The  other  series  of  acetylene 
compounds  of  mercury  are  not  generally  explosive, 
and  do  not  give  off  acetylene  with  dilute  acids  but 
evolve  acetaldehyde  when  heated  in  acids.  Moreover, 
whereas  the  carbides  give  di-iodacetylene  and  tetra- 
iodoethylene  when  treated  with  iodine,  the  non- 
explosive  products  obtained  from  acid  or  neutral 
solutions  of  salts  generally  appear  to  yield  iodoform. 
They  have  been  characterized  as  substituted  alde- 
hydes or  alcohols,  and  they  contain  the  metal  or  an 
acid-radicle  with  the  metal  in  the  place  of  one  or 
more  of  the  hydrogen  atoms  of  the  organic  compound. 

The  vinyl  derivatives  of  mercury  have  been  exten- 
sively studied  by  Polleck  and  Thiimmel. 1  They  gave 
off  acetaldehyde  when  attempts  were  made  to  obtain 
free  vinyl  alcohol  in  a  pure  state. 

In  1866,  Berthelot2  first  obtained  the  carbide  of 
mercury  resulting  from  the  action  of  acetylene  on  an 
alkaline  solution  of  a  mercury  salt.  He  did  not, 

JBer.  22,  (1889),  2863. 

2  Ann.  Chim.  Phys.  4,  9,  386. 


-  139  — 

however,  analyze  the  product  at  the  time  though  he 
noticed  its  explosive  properties.  The  acetylide  was 
made  by  passing  the  acetylene  into  a  solution  of 
mercuric  iodide  in  potassium  iodide  made  alkaline 
with  ammonia. 

Basset1  obtained  the  same  compound  from  Nessler's 
solution,  but  his  acetylene  appeared  to  have  been  im- 
pure. He  ascribed  to  it  the  formula,  C2H,HgI.,HgO. 

Keiser2  repeated  the  experiment  of  Basset  with  pure 
acetylene  and  his  results  indicated  that  the  product  of 
the  reaction  of  the  gas  upon  the  solution  of  mercuric 
iodide  and  potassium  iodide  in  potassium  hydroxide, 
had  the  formula,  C2Hg,  and  is  perfectly  analogous  to 
the  carbides  of  the  other  metals,  such  as  silver  or 
copper. 

In  1892,  Plimpton3  published  a  preliminary  notice 
of  his  work  upon  this  compound,  but  it  was  not  until 
1894  tnat  an  extended  study  of  the  subject  was 
completed.  In  1894,  Travers  and  Plimpton4  had  pre- 
pared the  explosive  carbide  of  mercury  in  a  number 
of  others  ways.  In  reference  to  Keiser 's  work 
they  intimated  that  they  could  not  obtain  the 
silver  compound  free  from  water,  and  they  gave  it 
the  formula,  3C2Hg.H2O. 

A  series  of  quite  different  compounds  was  obtained 
when  acetylene  was  passed  into  acid  or  neutral  solu- 
tion. Kutscherow,5  in  1883,  noticed  that  allylene 


1  Zeit.  f.  Chim.  (1869),  314,  and  Chem.  News,  19,  28. 

2  Amer.  Chem.  Jour.  15,  535. 

3  Proc.  Roy.  Soc.  ( 1894). 

4  Chem.  News,  69,  81  and  82,  i  Cent.  (1894),  549. 

5  Ber.  17,  13. 


—  140  — 

and  acetylene  passed  into  mercuric  chloride  gave 
precipitates.  He  analyzed  the  allylene  product  but 
does  not  seem  to  have  made  an  analysis  of  the  acety- 
lene derivative.  Pera  toner1  gave  it  the  formula, 
C2H2,3HgCl2,HgO. 

Keiser,2  however,  obtained  different  results.  He 
found  that  the  compound  contained  mercurous  mer- 
cury and  that  calomel  was  a  product  of  decomposition 
on  heating.  Though  not  able  to  separate  all  the 
water,  he  claimed  that  its  composition  is  represented 
by  the  formula,  C2(HgCl)2,  or  as  he  also  gives  it, 


Plimpton3  had  obtained  an  inexplosive  compound 
by  treating  mercuric  acetate  with  acetylene.  A  white 
precipitate  was  obtained  that  turns  gray  towards  the 
end  of  the  precipitation.  The  composition  of  the 
compound  was  held  to  be  3HgO.2C2H2,  and  the 
author  claimed  to  be  analogous  to  the  allylene  com- 
pound obtained  by  Kutscherow  3HgO,  2C3H4,  2HgCl2. 
lodoform  was  obtained  with  iodine  and  aldehyde 
with  dilute  acids. 

Berge  and  Reychler*  had  intimated  that  acetylene 
was  not  absorbed  by  an  acid  solution  of  mercuric 
chloride,  and  that  accordingly  this  could  be  used  to 
purify  acetylene. 

Biginelli5  proved  that  acetylene  was  absorbed  by 
Berge  and  Reychler's  solution  with  the  formation  of 

1  Gaz.  XXIV.,  II.,  (1894),  p.  42. 

2  Amer.  Chem.  Jour.  15,  535. 

8  Proc.  Chem.  Soc.  (1892),  109. 

4  Bull.  Soc.  Chim.  3,  17,  218. 

*  Ann.  di  Farm,  e  Chim.  (1898),  16.  Cent.  (1898),  925. 


the  definite  compound  Cl:CH(HgCl),  and  from  this 
other  substances  could  be  obtained  by  various  reac- 
tions. It  gave  aldehyde  when  heated  in  dilute  acid 
solution. 

Hofman1  in  1898,  obtained  from  acidified  mercuric 
nitrate,  a  substance  of  the  composition,  C2Hg2NO4H. 
As  he  obtained  the  same  substance  by  the  action  of 
acetaldehyde  on  acid  mercuric  nitrate,  he  gave  the 
acetylene  compound  the  constitutional  formula, 
C(Hg)(HgNO3)CHO,  so  that  he  considered  it  a  sub- 
stituted aldehyde.  He  showed  that  it  contained  the 
nitrate  group  and  that  it  gave  aldehyde  with  dilute 
acids. 

Erdman  and  Kothner2  tried  the  action  of  acetylene 
on  mercurous  nitrate,  and  obtained  a  compound  of 
the  formula,  C2(Hg3NO3)  +  H2O.  They  also  suc- 
ceeded in  obtaining  a  method  for  the  continuous 
preparation  of  aldehyde  from  acetylene  by  passing 
the  gas  into  a  boiling  solution  of  sulphuric  acid  to 
which  mercuric  oxide  or  a  mercury  salt  has  been 
added.  Kothner3  referred  to  the  fact  that  he  had 
obtained  a  compound  of  acetylene  with  mercuric 
nitrate,  and  had  given  it  the  formula,  C2Hg3NO4H2, 
or  as  it  was  afterwards  shown  to  be,  HgC:CHg-|- 
HgNO3-f  H2O.  He  claimed,  moreover,  to  have 
shown  its  relation  to  acetaldehyde  and  vinyl  alcohol, 
before  the  article  of  Hofman  had  appeared. 

Hofman*  criticised  Erdman  and  Kothner 's  work  on 


1  Ber.  31,  2475. 

2  Zeit.  An.  Chem.  18,  48. 

3  Ber.  31,  2475. 
*  Ber.  31,  2783. 


—  142  — 

the  ground  that,  if  they  had  known  the  relation  of 
the  mercury  compound  to  acetaldehyde,  they  would 
not  have  given  it  an  acetylide  formula.  Hofman 
claimed  that  the  product  of  acetylene  with  acidified 
mercuric  nitrate  was  neither  an  acetylide  nor  a 
mercurous  compound,  but  a  substituted  aldehyde. 
He  repeated  some  of  his  previous  experiments  with 
the  same  results  that  he  had  obtained  before,  and  he 
gave  the  compound  the  aldehyde  formula  : 

NO,Hg  H 


I  have  attempted  to  prepare,  among  others,  the 
fluoride  of  acetylene  and  mercury  by  passing  the  gas 
into  an  acidified  solution  of  mercuric  fluoride. 
Freshly  precipitated  mercuric  oxide  was  dissolved  in 
cold  concentrated  hydrofluoric  acid.  The  oxide  dis- 
solves readily  with  the  evolution  of  heat  when  the 
vessel  is  shaken  so  that  it  is  necessary  to  cool  the 
beaker.  All  the  glass  apparatus  used  was  well  coated 
with  paraffine  to  prevent  corrosion,  and  also  in  order 
to  prevent  the  subsequent  introduction  of  silica  as  an 
impurity  in  the  precipitated  mercury  fluoride  of 
acetylene.  When  no  more  mercuric  oxide  dissolved 
in  the  acid,  a  stream  of  acetylene  was  passed  into  the 
clear  filtered  solution.  A  white  flaky  precipitate  was 
immediately  formed.  At  a  certain  stage  of  the  reac- 
tion the  precipitate  began  suddenly  and  quickly  to 
turn  grayish  or  bluish  white.  In  order  to  obtain  the 
white  compound  free  from  the  gray  precipitate  the 
mixture  was  filtered  every  few  minutes  until  the 
product  began  to  change.  The  stream  of  gas  was 


then  continued  until  the  precipitation  ceased.  Both 
compounds  were  separately  washed  with  strong  hy- 
drofluoric acid.  They  were  then  washed  with 
alcohol  to  remove  water  and  finally  with  ether  to 
take  out  any  alcohol  remaining.  The  compounds 
were  then  dried  over  sulphuric  acid  in  a  dessicator 
for  several  weeks  to  a  constant  weight.  The  white 
compound  is  somewhat  soluble  in  strong  hydrofluoric 
acid,  insoluble  in  water,  alcohol,  or  ether.  It  is  a 
light  white  powder  resembling  the  product  of  the 
action  of  acetylene  on  neutral  mercuric  chloride, 
C2(HgCl)2,  examined  by  Keiser. 


ANALYSIS  OF  THE  WHITE  PRECIPITATE- 

.4834  grams  of  substance  gave  .4739  grams  of 
Mercuric  Sulphide. 

.6435  grams  of  substance  gave  .6298  grams  of 
Mercuric  Sulphide. 

PERCENTAGE  OF  MERCURY. 

Calculated  for          C2(HgCl)2,  Found 

Hg.  82.2  I.— 82.7 

II.— 82.4 

The  gray  compound  resulted  from  the  continued 
action  of  acetylene  on  acidified  mercuric  fluoride. 
It  resembled  in  nearly  every  respect  the  white  com- 
pound. Towards  the  end  of  the  reaction  free 
acetaldehyde  was  present. 


ANAI,YSIS    OF  THE    GRAY  PRECIPITATE. 

.4834  grams  of  the  compound  gave  .4041  grams  of 
Mercuric  Sulphide. 

.6435  grams  of  the  compound  gave  .6298  grams  of 
Mercuric  Sulphide. 

Calculated  for 


Hg.  83  3  I.—  83.6 

II.-S4.3 

These  compounds  are  insoluble  in  dilute  acids,  and 
soluble  in  warm  concentrated  nitric  acids  with  the 
formation  of  mercurous  nitrate.  Caustic  potash  pre- 
cipitates from  the  diluted  nitric  acid  solution 
mercurous  oxide.  When  hydrogen  sulphide  is 
passed  into  the  compounds  suspended  in  water,  they 
turn  black  and  acetaldehyde  and  thioaldehyde  are 
formed.  Acetaldehyde  and  thioaldehyde  are  also 
formed  when  the  substances  are  treated  with  am- 
monium sulphide,  and  then  neutralized  with 
hydrochloric  acid.  With  concentrated  hydrochloric 
acid  a  strong  reaction  takes  place  with  the  evolution 
of  hydrofluoric  acid,  and  the  formation  of  the  com- 
pound, C2(HgCl)2,  analyzed  by  Keiser. 

C2(HgF)2+2HCl=C2(HgCl)2+2HF. 

Dry  bromine  reacts  so  energetically  with  the  sub- 
stance that  the  latter  is  carbonized  on  contact. 
Bromine  water  gives  rise  to  traces  of  an  oil  that  is 
probably  bromoform,  or  bromacetylene.  Dry  chlo- 
rine also  decomposes  the  mercury  acetylene  fluoride 
with  the  evolution  of  much  heat,  and  the  formation 


—  H5  — 

of  a  small  amount  of  oil.  The  products  resulting 
from  the  action  of  bromine  and  chlorine  have  not 
been  carefully  studied.  A  solution  of  iodine  and 
potassium  iodide  gives  rise  to  iodoform.  A  better 
yield  of  iodoform  is  obtained  by  boiling  the  com- 
pound with  iodine  and  sodium  carbonate.  The 
iodoform  was  very  pure  and  after  its  first  crystal- 
ization  from  alcohol  melted  exactly  at  ii9°C. 

The  acetylene  compound  of  mercuric  fluoride 
dissolves  in  chloric  acid,  or  potassium  chlorate  and 
hydrochloric  acid,  and  mercuric  chloride  is  obtained. 
The  fact  that  the  mercury  in  the  compound  is  in  the 
mercurous  condition,  and  that  the  substance  readily 
unites  with  water  in  the  presence  of  dilute  acids 
giving  rise  to  acetaldehyde,  seems  to  point  to  the 
fact  that  it  may  be  a  substituted  aldehyde  of  the 
formula,  CH(HgF)2CHO.  It  may  also  be  a  sub- 
stituted vinyl  alcohol  which  also  would  give  rise  to 
acetaldehyde  when  decomposed.  The  production  of 
iodoform  also  indicates  this.  The  mode  of  formation 
of  the  compound  may  be  represented  as  follows : 

C2H2+2HgF2=C2(HgF)2+2HF,  or, 

C2(HgF)2+HOH  =  CH(HgF):C(HgF)OHor, 

CH(HgF)2CHO. 

The  formation  of  acetaldehyde  from  the  compound 
is  represented  thus . 

CH(HgF):C(HgF)OH+2HF=(CH2:CHOH)+ 

2HgF2, 
(CH2:  CHOH)  =CH3CHO. 


—  I46  - 

There  is  more  evidence  in  favor  of  the  vinyl 
alcohol  formula  for  the  compound.  If  the  mercury 
derivative  had  an  aldehyde  formula  it  would  probably 
be  likely  that  it  could  be  formed  from  acetaldehyde 
and  mercuric  fluoride  solution.  Acetaldehyde  does 
not  react  with  mercuric  fluoride  with  the  formation 
of  a  precipitate. 

It  is  most  likely  then  a  vinyl  derivative  that  gives 
off  acetaldehyde  when  decomposed.  It  is  analogous 
to  the  vinyl  mercury  derivatives  prepared  by  Polleck 
and  Thiimmel. 

Keiser's  compound,  C2(HgCl)2+H2O  is  none  other 
than  the  product,  CH(HgCl):  C(HgCl)OH  prepared 
by  Polleck  and  Thiimmel  from  ether  derivatives. 


In  conclusion  I  wish  to  thank  Mr.  W.  Waggaman 
for  his  kind  assistance  in  supplying  me  with  the 
electrodes  of  calcium  carbide  used  in  the  electrolytical 
experiments.  I  thank  him  also  for  assisting  me  to 
set  up  the  apparatus,  etc. 


Notre  Dame,  Indiana, 
October,  1904. 


—  147  — 


BIOGRAPHICAL. 


Julius  A.  Nieuwland  was  born  near  Ghent, 
Belgium,  February  14,  1878.  In  1880,  his  parents 
came  to  the  United  States,  and  settled  in  South 
Bend,  Ind.  His  first  instruction  was  received  in 
St.  Mary's  parochial  school  in  that  place.  In  Sep- 
tember, 1892,  he  entered  the  preparatory  courses  at 
Notre  Dame  University,  and  was  graduated  with  the 
degree  of  Bachelor  of  Arts  in  1899.  After  a  novitiate 
in  the  Congregation  of  Holy  Cross,  at  Notre  Dame, 
Ind.,  he  entered  Holy  Cross  College,  Washington, 
D.  C. ,  where  he  pursued  his  theological  studies.  He 
was  -ordained  to  the  priesthood  December  19,  1903. 
Having  entered  the  Catholic  University  of  America 
in  1900  as  a  graduate  student  in  the  Faculty  of 
Philosophy  he  followed  the  course  of  chemistry  as  a 
major  subject,  and  botany,  experimental  psychology 
and  biology  as  subordinate  studies. 


—  148  — 


INDEX. 


PART  I. 

HYDROGENATION  OE   ACETYLENE I 

History  of  the  Synthesis  of  Ethylene I 

1. — Action  of  Sulphuric  Acid  on  Acetylene 9 

History   of  the  Reaction   of  Sulphuric     Acid    on 

Acetylene 9 

Acetylene  and  Strong  Sulphuric  Acid 13 

Acetylene  and  Dilute  Sulphuric  Acid 15 

Formation  of  Acetaldehyde  and   Thioaldehyde. 

Acetylene  and  Nitrosulphonic  Acid 16 

Acetylene  and  Chlorsulphonic  Acid 16 

,   Acetylene  and  Sulphur  Trioxide 17 

History  of  Reaction  of  Sulphur   Trioxide   with 

Ethylene 17 

Formation  of  Acetylene  Carbyl  Sulphate 18-21 

Analogy  of  the  Reactions  of  Acetylene  and  Ethylene 

toward  Derivatives  of  Sulphuric  Acid 21 

Synthesis  of  Aldehyde  from  Water  and  Acetylene 

in  the  Presence  of  Dilute  Nitric  Abid 28 

Resume  of  Results 30 

II. — Action  of  Sulphuric  Acid  on  Calcium  Carbide 31 

Calcium  Carbide  and  Strong  Sulphuric  acid 31 

First  Method  of  Experiment. 
Second  Method  of  Experiment. 

Calcium  Carbide  and  Dilute  Sulphuric  Acid 33 

Formation  of  Thioaldehyde. 
Calcium    Carbide    and    Stronger    Sulphuric    Acid 

without  Heating  (Acid  sp.  gr.  1.82  to  1.84) 34 

Formation  of  Crotonaldehyde. 

Calcium  Carbide  and  Monohydrated  Sulphuric  Acid,  36 
II. — Electrolysis  of  Various  Solutions   with  Calcium 

Carbide   Electrodes 37 

Methods  of  Analysis 37 


-  149  - 

Electrolysis    of    Sulphuric     Acid     with    Calcium 

Carbide  Electrodes 40 

Electrolysis    of     Strong    Sulphuric    Acid.  (Pre- 
liminary Experiment) 40 

Electrolysis  of  Dilute  Sulphuric  Acid 48 

First  Series  of  Experiments 48 

Second  Series  of  Experiments 50 

Third  Series  of  Experiments 53 

Electrolysis  with  Slight  Pressure. 

Electrolysis  of  Calcium  Hydroxide  Solution 56 

Electrolysis  of  Calcium  Chloride  Solution 57 

At  Ordinary  Temperature 59 

At  Higher  Temperature 61 

Electrolysis  of  Zinc  Chloride  Solution 63 

Electrolysis  of  Calcium  Nitrate  Solution 64 

Under  Ordinary  Conditions 64 

Under  Increased  Pressure 65 

At  Higher  Temperatures 70 

Electrolysis    of  Nitrates    at    Temperatures    above 

100°  C 70 

Electrolysis  of  Calcium  Nitrate 70 

Electrolysis  of  Zinc  Nitrate 71 

Electrolysis  of  Mercuric  Nitrate 74 

General  Conclusions.. 72,  74-76 

PART  II. 

CHIvORINATlON  OF  ACETYLENE 77 

History  of  Reaction  of  Chlorine  and  Acetylene 77 

1ST  DIVISION. 

I. — Direct  Action  of  Chlorine  Gas  on  Acetylene  Gas 84 

i. — Acetylene  and  Chlorine  Hydrate 85 

2. — Action  of  a  Solution  of  Acetylene  in  Acetone 
towards    a    Solution    of   Chlorine  in    Carbon 

Tetrachloride 86 

3.  — Direct  Union  of  Chlorine  and  Acetylene  atl/ow 

Temperatures 87 

4. — Chlorine  and  Acetylene  at  100°  C 91 


-  150- 

5- — Chlorine     and     Acetylene    at      Temperatures 
above  100°  C 92 

2ND  DIVISION. 

II. — Action  of  Acetylene  towards  Chlorides  and  Chlorin- 
ating Agents 95 

A. — Reaction  of  Sulphuryl  Chloride  with  Unsaturated 

Hydrocarbons 95 

History  of  the  Reactions  of  Sulphuryl  Chloride 95 

The  "Dissociation  Theory"  of  Ruff 97 

i.— Chlorination    of    Acetylene     with     Sulphuryl 

Chloride  in  Presence  of  Aluminium  Chloride 100 

Formation  of  Tetrachlorethane 101,  102,  108 

Formation  of  Sulphone  Chlorides 105,  106-108 

Formation  of  Hexachlorethane 106 

Formation  of  Tetrachlorethylene. 

Discussion  on  the  Action  of  Sulphuryl  Chloride  in 

Presence  of  Aluminium  Chloride 109 

Reversibility  of  the  Reaction in 

Conclusions 112 

2.— Chlorination    of     Ethylene     with     Sulphuryl 

Chloride  in  the  Presence  of  Aluminium  Chloride,  1 13 

Formation  of  Ethylene  Chloride 113,  115 

Formation  of  Tetrachlorethane 114 

Formation  of  Chlorisethionyl  Chloride 115,  116 

3. — Chlorination  of  Amylene  with  Sulphuryl  Chloride. 
Formation  of    Dichlorpentane  and  Trichlorpentane. 

A. — Reaction  of  other  Chlorides  with  Acetylene 117 

i. — Acetylene  and  Disulphur  Dichloride  (S2C12) 117 

Formation  of  Tetrachlorethane  and  Derivatives. 

2. — Acetylene  and  Sulphur  Dichloride  (SC12) 120 

3.— Thionyl  Chloride,  (SOC12)  and  Acetylene 121 

4.— Stannic  Chloride,  (SnCl4)  and  Acetylene 121 

5. — Plumbic  Chloride,  (PbCl4),  Plumbic  Ammonium 

Chloride  (PbCl42NH4Cl),  and  Acetylene 122 

6.— Carbonyl  Chloride,  (COC12)  Cyanogen  Chloride 

(CnCl)  and  Nitrosyl  Chloride  (NOC1) 122 

7. — Antimony  Trichloride  (SbCl3)  and  Phosphorus 
Pentachloride  (PC15) 122 


8.— Chromyl  Chloride  CrO2Cl2) 123 

9. — Arsenic  Trichloride  (AsCl3) 123 

io.— Acetylene  and  Dry  Iodine  Trichloride(ICl3)....i24 

Formation  of  Tetrachlorethane. 
II. — Acetylene  and  "Aqua  Regia" 126 

Formation  of  Tetrachlorethane,  Hexachlorethane 

and  Nitro-derivatives. 
12. — Acetylene  and  Antimony  Pentachloride 128 

Laboratory  Method  of  Preparing  Tetrachorethane,  136 


APPENDIX. 

REACTION  OF  ACETYLENE  TOWARDS  ACIDIFIED  MERCURIC 

FLUORIDE 138 


OF  THE 

UNIVERSITY 

OF 


—  152  — 


ERRATA. 


On  page  17,  line  19,  read  "water"  for  "the  anhydride.' 

On  page  67,  line  16,  put  "(C)"  for  "(G)." 

On  page  67,  line  27,  for  "tighty  "  read  "tightly." 

On  page  83,  line  i,  for  "derivities"  read  "derivatives." 

On  page  95,  line  3,  in  title,  put  "reaction"  for  "reation. 

On  page  100,  line  15,  read  "retarded  '  for  "  retailed." 

On  page  113,  line  i,  insert  "to"  after  "due,"  to  read  ' 

was  probably  due  to,"  etc. 
On  page  121,  line  9,  read  "ordinary  "  for  "oridinary." 


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